3

3

3

MORPHOLOGY AND SYSTEMATICS

3.1

INTRODUCTION

Nalepa (1887) reported the first significant information on the external morphology of eriophyoid mites from studies on slide-mounted specimens using light microscopy. From the 1940s onwards phase contrast light microscopy facilitated improved study of eriophyoid mite morphology. This led to improved descriptions, with the standard set by the publications of Keifer (e.g., Keifer,

1952b, 1959a, Baker et al., 1996). Eriophyoid morphology for systematic use is still, almost exclusively, studied on cleared and slide-mounted specimens, using phase contrast (Fig. 3.1a).

These data form the basis of the classification and identification of the Eriophyoidea. Taxon descriptions are accompanied by drawings, either realistic (drawn with the aid of a drawing tube or camera lucida with little or no modification) (e.g., Craemer et al., 1999 and Amrine et al., 1994), semi-schematic (drawn with the aid of a drawing tube with modification to represent characteristics of the species clearly) (e.g., Keifer, 1954) – of which a part is depicted in Fig. 3.1b, and e.g., Denizhan et al. (2007), or more schematic (e.g., Kuang, 1986a). Eriophyoid descriptions still largely follow the standard and format set by Keifer (Nuzzaci & De Lillo, 1996; De Lillo et

al.

, 2010).

a b

Fig. 3.1. Coxisternal plates and external genitalia of a slide-mounted female specimen of Cecidophyopsis sp. cf. C.

hendersoni

(Keifer, 1954): a) digital image of slide-mounted specimen viewed with phase contrast light microscopy; b) taxonomic drawing of the same area of C. hendersoni by Keifer (reproduced from Keifer, 1954).

Chapter 3. Morphology.

36

The morphology of the Eriophyoidea is presented by various authors (including Channabasavanna,

1966; Shevchenko, 1970; Keifer, 1975a,b; Manson, 1984a; Amrine, 1996; Lindquist & Amrine,

1996; Amrine et al., 2003), with a comprehensive review by Lindquist (1996a). Lindquist (1996a) additionally proposed hypotheses of primary homologies between eriophyoid structures and those of other acariform mites, applying the system of standardized terminology and notation of the

Acariformes to the Eriophyoidea. This system is generally accepted and adopted by eriophyoid systematists worldwide and its terminology is used in this dissertation. Figures 3.2–3.6 depict the general morphological characters, and Figs 3.19–3.23 depict characters of the eriophyoid gnathosoma, as typified by some general schematic drawings and representative species.

The classification of the Eriophyoidea constructed from morphological studies of slide-mounted specimens (Newkirk & Keifer, 1975; Boczek et al., 1989; Amrine, 1996 and Amrine et al., 2003), despite some contention between the classifications, are relatively stable and workable. The groupings, however, may be artificial (see Chapter 4). Identification keys to the genera of the

Eriophyoidea worldwide by Amrine (1996) and Amrine et al. (2003) are generally accepted today, and identification, description and differentiation of eriophyoid taxa at all levels are more or less satisfactory using data from only slide-mounted specimens, although problems in certain groups and in some morphological and taxonomic aspects exist.

Chapter 3. Morphology.

37

a

prodorsum opisthosoma in some taxa, e.g., Phytoptus spp., seta c1 (c1) occurs in this area gnathosoma leg I annuli

b

gnathosoma seta sc

(sc) seta c2 (c2) seta d (d) leg I seta 3a (3a) microtubercles seta e (e) anal lobe leg II female external genitalia prodorsal shield frontal lobe seta f (f) seta h2 (h2) seta h1 (h1) seta sc

(sc) scapular setal tubercle or sc setal tubercle dorsal annulus width (conventional use) (it can be regarded as the length parallel to long axis of body length) dorsal annuli leg II seta c2 (c2) seta 3a (3a) seta d (d) seta e (e) ventral annuli seta f (f) telosome

sensu

Keifer (term not used in present study) seta h1 (h1) seta h2 (h2)

Fig. 3.2. Habitus of the two major forms of eriophyoid mites in lateral view: a) vermiform mite, Aceria sp. nov.

(Eriophyidae), digitally drawn by C. Craemer from a SEM image. Vermiform eriophyoids usually live a relatively sheltered life within micro-spaces e.g., in galls or under bud scales; b) fusiform mite, Rhynchaphytoptus ficifoliae Keifer

(Diptilomiopidae), drawn by E. de Lillo (De Lillo, 1988b) from slide mounted specimens, with confirmation of morphology from SEM images. Fusiform eriophyoids usually live a more exposed life, e.g., rust mites. Additionally

Rhyncaphytoptus has the large, typical shaped gnathosoma characteristically of the Diptilomiopidae. Note that the quality of the two drawings can not be compared here, because (a) is a print of an original vector drawing and (b) is a scanned image of a photocopy of the original article by De Lillo (1988b). Drawing is used with permission from the author.

Chapter 3. Morphology.

38

a

seta sc (sc) leg II leg I gnathosoma prodorsal shield single seta vi (single vi) seta c1 (c1) seta c2 (c2)

b

seta h1 (h1) seta h2 (h2) admedian line median line submedian lines scapular setal tubercles

c

seta sc near shield rear margin, directed divergently posteriad

d

seta ve (ve) paired seta vi

(paired vi) seta sc1 (sc1) seta sc2

(sc2)

h

seta ve

(ve)

e

single seta vi

(single vi) seta ve (ve) seta sc (sc) paired seta vi

(paired vi)

i

seta ve (ve) seta sc (sc)

l j f

single seta vi

(single vi) seta sc (sc) seta ve (ve) seta sc ahead of shield rear margin, directed anteriad

g k

single seta vi

(single vi) seta sc (sc)

Fig. 3.3. a) Habitus of an eriophyoid mite, represented by the SEM image of Trisetacus sp. (Eriophyoidea: Phytoptidae) in dorsal view, scale line = 10 µm; b, c) schematic drawings of prodorsal shield in dorsal view with names of general lines of prodorsal shield pattern, and different positions and projections of sc. Schematic representation of different setal patterns on the prodorsum in dorsal view: d) eight setae, e.g., members of the Tydeidae; e) five setae (maximum number of prodorsal setae in the Eriophyoidea), only present in Pentasetacus (Phytoptidae: Nalepellinae); f) three setae, e.g.,

Trisetacus (Phytoptidae: Nalepellinae); g) one seta, e.g., Boczekella (Phytoptidae: Nalepellinae); h) four setae anteriorly on shield, e.g., Prothrix (Phytoptidae: Prothricinae), but the internal pair of setae may not be paired vi, but rather sc which moved far forward (see Chapter 4); i) four setae, two anteriorly on shield, two closer to the shield rear margin, e.g.,

Novophytoptus (Phytoptidae: Novophytoptinae); j) two setae anteriorly on shield, e.g., Propilus (Phytoptidae:

Sierraphytoptinae: Mackiellini); k) two setae, sc, mostly on posterior part of dorsal shield, in most species of the

Eriophyidae and Diptilomiopidae; l) no setae e.g., Cecidophyes (Eriophyidae: Cecidophyinae).

Chapter 3. Morphology.

39

leg I leg II seta sc

(sc) seta bv

(bv) seta 1b (1b) seta 1a (1a) seta 2a (2a) seta c2

(c2) seta 3a

(3a) seta c2

(c2) seta d (d) seta e (e) frontal lobe gnathosoma coxisternal plate I position of prosternal apodeme coxisternal plate II few microtubercles on basal part of genital coverflap one rank of longitudinal ridges on distal part of genital coverflap female genital coverflap ventral annuli with microtubercles dorsal annuli seta f (f) seta h2 (h2) caudal lobe

Fig. 3.4. Habitus of an eriophyoid mite, represented by the SEM image of an Aculus sp. (Eriophyoidea: Eriophyidae:

Phyllocoptinae) in ventral view. Scale line = 10 µm.

Chapter 3. Morphology.

40

a b c

seta 1a (1a)

d

seta 1b (1b) seta 2a

(2a)

3a

inter coxi-genital area with coxi-genital annuli seta 3a (3a) realistically depicted in (a) and semischematic in (b) anterior genital apodeme folded up and shortened, appearing as a heavy transverse line spermathecum round spermathecal tube short distal part of genital coverflap with two uneven ranks of longitudinal ridges coxisternal plate I, granulated

e

anterior genital apodeme extending a relatively moderate distance anteriad coxisternal plate II, granulated spermathecal tube short spermathecum round prosternal apodeme basal part of genital coverflap with one transverse row of microtubercles distal part of genital coverflap with one rank of longitudinal ridges

f

spermathecal tube short

g

anterior genital apodeme folded up and shortened anterior genital apodeme extending a relatively moderate distance anteriad

h

1b

2a

1a

i

spermathecum elongated inter coxi-genital area long, with genitalia a relatively long distance away from coxisternal plates spermathecal tube long

3a

distal part of genital coverflap unornamented

(smooth) basal part of genital coverflap probably with one rank of short longitudinal ridges (not described in original description) spermathecum somewhat elongated distal part of genital coverflap unornamented (smooth)

Fig. 3.5. Descriptive drawings of the coxi-genital areas and internal genitalia of slide-mounted adult females of different eriophyoid taxa. Cecidophyes rouhollahi Craemer, 1999 (Eriophyidae: Cecidophyinae), reproduced from Craemer et al.

(1999), specimen depicted in (a) more flattened under coverslip than specimen depicted in (b): a) coxi-genital area, drawing by C. Craemer, b) coxi-genital area, drawing by H.H. Keifer, c) internal genitalia, drawing by C. Craemer;

Tegolophus califraxini (Keifer, 1938b) (Eriophyidae: Phyllocoptinae), drawings by E. de Lillo, reproduced from De Lillo

(1988b): d) coxi-genital area, e) internal genitalia; Novophytoptus stipae Keifer, 1962, drawings by H.H. Keifer, reproduced from Keifer (1962d): f) internal genitalia, g) coxi-genital area; Trisetacus cupressi Keifer, 1944, drawings by

H.H. Keifer, reproduced from Keifer (1944): h) internal genitalia (modified from Keifer, 1944), i) coxi-genital area. All reproductions with permission where necessary.

Chapter 3. Morphology.

41

a) Leg I

seta l’’ (l’’) femur trochanter genu seta bv (bv) seta l’ (l’) sensu Lindquist; in future possibly named seta l (present study) seta ft’ (ft’) (dorsal tarsal seta

sensu Keifer) tibia seta ft’’ (ft’’) (lateral tarsal seta sensu Keifer) empodium solenidion T tarsus seta u’ (u’)

b) Leg II

spinules on margin between femur and genu tibia (no setas present on tibia of leg II of the Eriophyoidea) solenidion T seta ft’ (ft’) seta l’’ (l’’) femur note the differences between the shape and number of sub-rays between the drawing by C. Craemer (left) and H.H. Keifer (right) of the same species seta ft’’(ft’’) empodium tarsus seta u’ (u’) genu trochanter seta bv

(bv)

c)

simple, with 5 rays

d)

simple, with 5 rays

e)

simple, distally elongated

f)

simple, rays unsymmetrical

g)

partly divided

h)

divided

i)

divided, stems unequal

j)

divided, stems pad-like with numerous rays

k)

divided, with central stem

l)

palmate

m)

basal rays finely branched, hair-like

n)

reduced to bristle

Fig. 3.6. Legs and leg structures of adult eriophyoid females. Legs of Aculops rhodensis (Keifer, 1957) as drawn by E. de

Lillo, from De Lillo (1988b): a) leg I; b) leg II. Different shapes of eriophyoid empodia (featherclaws) of various species:

c) Cecidophyes rouhollahi, drawing by C. Craemer (reproduced from Craemer et al., 1999); d) C. rouhollahi, drawing by

H.H. Keifer (reproduced from Craemer et al., 1999); e) Dicrothrix anacardii Keifer, 1966 (reproduced from Keifer,

1966b); f) Dechela epelis Keifer, 1965 (reproduced from Keifer, 1965a); g) Acaphyllisa parindiae Keifer, 1978

(reproduced from Keifer, 1978); h) Diptilomiopus faurius sp. nov. (Appendix L); i) Acarhis lepisanthis Keifer, 1975

(reproduced from Keifer, 1975d); j) Acarhynchus filamentus Keifer, 1959 (reproduced from Keifer, 1959b); k)

Diptiloplatus megagrastis Keifer, 1975 (reproduced from Keifer, 1975c); l) Acritonotus denmarki Keifer, 1962

(reproduced from Keifer, 1962b); m) Brevulacus reticulatus Manson, 1984, protogyne female (modified from Manson,

1984a); n) Aberoptus samoae Keifer, 1951, leg I (modified from Keifer, 1951). Terminology sensu Keifer not used in the present study.

Chapter 3. Morphology.

42

Although the amount of character variation is roughly sufficient for standard taxonomy, some characters demarcating different genera, and even higher groupings, are not of good taxonomic value, and somewhat vague and subjective, and sometimes with intergradation between them

(Amrine et al., 2003). For instance, differentiation between the tribe Tegonotini (with lateral lobes or pointed projections from some or all annuli, or with a plate behind prodorsal shield bearing lateral extensions) and the tribes Phyllocoptini and Anthocoptini (without these lateral opisthosomal projections); between Aculus (anterior shield lobe broad and rounded) and Aculops

(anterior shield more acuminate, frequently ending in a sharp point); between Tegonotus (sc ahead of rear shield margin, direction variable) and Shevtchenkella (sc on rear shield margin, directed posteriorly); between Aceria (posterior opisthosoma with annuli continuous and subequal dorsoventrally) and Paraphytoptus (posterior opisthosoma with wider annuli dorsally); and between Epitrimerus (middorsal ridge fading simultaneously with subdorsal or lateral ridges) and

Calepitrimerus

(middorsal ridge ending in a broad furrow before termination of subdorsal ridges)

(Amrine et al., 2003), are contentious.

Furthermore, the differentiation between species and the identification of these species of some very large genera, e.g., Aceria with more than 900 species worldwide, are also becoming problematic (Amrine et al., 2003). Very few species identification keys are available for, example,

Aceria

, and those available pertain to species over limited geographic areas (e.g., Meyer &

Ueckermann, 1990).

It is evident that there are not enough morphological characters documented and available for phylogenetic analyses, and most of these were found to be highly homoplasious by previous studies (Hong & Zhang, 1996a, b, 1997), as well as by the present phylogenetic study (see Chapter

4). Additional characters with more phylogenetic information (homologous or at least less homoplasious characters) will be of tremendous use in finding more clades and more robust and reliable hypothesized phylogenetic relationships between taxa.

Many of these systematic problems can be rectified or improved by the discovery of additional new systematically informative characters for the currently known species, apart from those characters that will be obtained from the discovery of new species. Despite the relative simplicity and reduction of the eriophyoid body, the group is unexpectedly diverse in morphology (Amrine,

1996; Lindquist, 1996a; Amrine et al., 2003). There are, however, not many additional taxonomically informative and useful characters available from slide-mounted specimens.

Taxonomic characters for the Eriophyoidea are already obtained from the entire body (Lindquist &

Amrine, 1996; Amrine et al., 2003), and most easily observable and taxonomically useful

Chapter 3. Morphology.

43

characters are already utilized. The degree of morphological diversity is also limited by the lack of ontogenetic diversity in characters (characters have the same states throughout all life stages), and the lack of distinctive characters in the male (Lindquist & Amrine, 1996).

The quality of the systematics of the Eriophyoidea is dependent on the quality of the taxonomic descriptions, of which exact, detailed drawings should be an integral part (Keifer, 1975a, b;

Amrine, 1996; Amrine et al., 2003; De Lillo et al., 2010). In practice, even in recent publications, many descriptions and drawings do not achieve the required standard and in particular do not always convey exact taxonomically important detailed characteristics (Amrine & Manson, 1996;

De Lillo et al., 2010). It also became clear during the present study (Chapters 4), particularly when using published descriptions, that the characters are frequently not well-defined and demarcated, and this presents problems for the determination of primary homologies in obtaining a taxon x character state matrix for phylogenetic analyses. Thorough and precise descriptions of eriophyoids are extremely important when it is taken into account that slide-mounted specimens are not permanent, and that most type material is lost over time (Amrine & Manson, 1996; De

Lillo et al., 2010).

There are many problems with the quality and standardization of slide-mounted specimens

(Amrine & Manson, 1996; De Lillo et al., 2010), and the resultant quality of eriophyoid descriptions. Another technique for studying morphology is electron microscopy (EM) which facilitates higher resolution than light microscopy, and is largely superior to light microscopy for studying minute organisms with ultra-fine structures. Following the development of electron microscopy and its eventual utilization for studying eriophyoid morphology, more information on the external and internal morphology of eriophyoid mites was obtained, and our understanding of and knowledge on their morphology have improved (Nuzzaci & De Lillo, 1996).

Information on the internal structures of eriophyoids was largely obtained with transmission electron microscopy (TEM), reviewed by Nuzzaci & Alberti (1996). Some of the first TEM studies undertaken on the Eriophyoidea were those of Paliwal & Slykhuis (1967) and Takahashi &

Orlob (1969) on the intestines of Aceria tosichella with the focus on virus vectoring. Subsequent studies include Shevchenko & Silvere (1968), Nuzzaci & Liaci (1975), Nuzzaci (1976a, 1979),

Thomsen (1987, 1988), Nuzzaci & Alberti (1996), and Nuzzaci & De Lillo (1991), and essentially focused on the functional morphology of various structures.

The first published studies on the external morphology of the Eriophyoidea with EM were undertaken with TEM (Proeseler & Eisbein, 1968; Eisbein & Proeseler, 1969). Hereafter, external

Chapter 3. Morphology.

44

morphology was mainly studied with scanning electron microscopy (SEM) which is more appropriate for studying surface structures.

Scanning electron microscope images of eriophyoids can be found in Keifer (1975a, b) and

Lindquist (1996a). Only a few comprehensive morphological studies, but on a single species or only a few species, using SEM have been published, and these mostly focused on the functional morphology of particular body regions, or demonstrated SEM techniques [e.g., Whitmoyer et al.,

1972; Gibson, 1974; McCoy & Albrigo, 1975 (mouth-parts and feeding); Hislop & Jeppson, 1976

(mouth-parts and feeding); Nuzzaci, 1976a, b; Nuzzaci & Vovlas, 1976; Schliesske, 1978; Baker

et al.

, 1987; Westphal et al., 1990; Amrine et al., 1994; Duffner et al., 1998; Huang, 1999; Wergin

et al.

, 2000; Achor et al., 2001; Freeman et al., 2005]. Other SEM studies confirmed or elucidated internal gnathosomal structures (Thomsen, 1987; Freeman et al., 2005), or focused on spermatophores deposited by eriophyoid males (e.g., Oldfield et al., 1970; Duffner et al., 1998).

Scanning electron microscope images are sporadically incorporated in taxonomic articles, but they are usually merely used to enhance and confirm taxonomic descriptions from slide-mounted specimens, and are included in the articles normally without particular comment or focus on them.

They are mostly not used to add additional morphological or descriptive information (e.g., Keifer

et al.

, 1982; Boczek & Nuzzaci, 1985; Schliesske, 1985; De Lillo, 1988b; Chandrapatya &

Boczek, 1991a,b; Boczek & Chandrapatya, 1992a; Amrine et al., 1994; De Lillo, 1994; Huang &

Wang, 2004). Only images of entire mites are usually included, while a few included some enlargements of particular body regions (e.g., Amrine et al., 1994). The SEM images probably contributed to the correctness and detail of the descriptions. A few authors based descriptions on

SEM images (e.g., Huang, 1992) without the inclusion of descriptive drawings. Amrine (1996) condemned this practice, and De Lillo & Skoracka (2010) likewise strongly advised against the use of SEM images in place of drawings.

De Lillo & Aldini (2001) combined TEM and SEM to study and compare the ultrastructure of sensory structures on the leg tarsi of a species of the Siteroptidae and Phytoptus avellanae

(Phytoptidae), Aculops lycopersici (Tryon) (Eriophyidae) and Diptacus hederiphagus Nuzzaci

(Diptilomiopidae) of the Eriophyoidea. They found the wall of the tarsal solenidion shaft of P.

avellanae

is smooth and without pores, but it has very small apical pores forming a complex system connected with pore tubules. They could not see the pores in SEM images. In contrast, the siteroptid solenidial shaft has a multiporous wall enclosing several dendritic branches, and no tubular bodies are associated with the solenidion. They concluded that the solenidia of these species are both isotropic, but based on clear differences in cuticular and cytological

Chapter 3. Morphology.

45

characteristics these were found to be of different types. Before homologies between many structures, especially between structures in the Eriophyoidea and other mite groups, can be determined, anatomical and functional relevance should be taken into consideration, in addition to external morphological information (De Lillo & Aldini, 2001).

Alberti & Nuzzaci (1996) comprehensively reviewed the SEM and TEM techniques used for studying eriophyoid mites, focusing on conventional methods. Various techniques for SEM preparation and study of biological material are available. The microscopic size, soft and delicate bodies, and ultra-fine structural details of the Eriophyoidea causing difficulties with preparing and studying slide-mounted specimens, also pose problems for SEM techniques.

Conventional SEM preparation methods broadly entail fixation, dehydration and final drying of the specimens. Unfortunately, these preparation methods are associated with artefacts in biological specimens (Sutherland & Hallett, 1987), of which deformation caused by shrinking of the material is the most prevalent, and shrinking is particularly a problem in the soft-bodied eriophyoid mites [Craemer & Hall, 2003 (Appendix J.1.)]. With these methods, the mites usually have to be removed from their natural habitat and position (Alberti & Nuzzaci, 1996).

It is possible to observe live or “fresh” specimens in the SEM, avoiding fixation and dehydration (Woolley, 1970). Nuzzaci & Vovlas (1976) and Alberti & Nuzzaci (1996) described a similar method modified for eriophyoid mites. Another method, the so-called

“acrolein method”, for successfully studying eriophyoids intact in a natural state was used by

McCoy & Albrigo (1975) and Hislop & Jeppson (1976), and is also described by Alberti &

Nuzzaci (1996). There are also SEM techniques available for preparing dry eriophyoid material, already preserved specimens and slide-mounted specimens (Nuzzaci & De Lillo,

1991; Alberti & Nuzzaci, 1996).

Low-temperature SEM, also known as cryo-SEM, with an integrated high vacuum freezing and sputter unit, seems to be the most successful SEM technique in obtaining highly magnified, largely artefact-free images of eriophyoid mites, particularly minimizing shrinkage

(Sutherland & Hallett, 1987; Duffner et al., 1998; Wergin et al., 2000; Achor et al., 2001).

The first images of eriophyoid mites obtained by using cryo-SEM were published by Amrine

et al.

(1994). Achor et al. (2001) compared results of mites studied with ambient temperature

SEM (using four preparation techniques), and low-temperature (cryo-) SEM. Lowtemperature SEM was found to be superior to the conventionally used ambient temperature

SEM. Wergin et al. (2000) described a modified cryo-fixation procedure that can be used for low-temperature SEM, retaining the mites in their living/feeding sites in natural behavioral

Chapter 3. Morphology.

46

positions, and again confirmed that the turgor of eggs and the soft-bodied eriophyoids were maintained. Using a field emission SEM which provides superior resolution to what can be attained with conventional SEM, allowed better resolution and discrimination of ultra structural features (Wergin et al., 2000).

The aims of and motivation for the present SEM study are set out in Chapter 1. One major aim is to investigate to what extent SEM studies may contribute to obtaining additional morphological characters, and how much it can improve the description of eriophyoid morphology, and to what extent it could or should be incorporated in the systematics of the Eriophyoidea, and particularly in phylogenetic analyses of this group.

The results and discussion of the SEM study of eriophyoid morphology is presented in two parts:

Part I entails a general overview of the improvement of morphological study obtained in the present SEM study. Some results obtained with SEM are compared with slidemounted specimens or published descriptions of these. Light microscopic study of the morphology of eriophyoid mites obtained from slide-mounted specimens and its application in their systematics is broadly appraised.

Part II entails a comparative morphological study of the gnathosoma, of all the species in the present SEM study. It is included to illustrate to what extent SEM studies can contribute towards systematics, and to present the new data. Similar comparative studies, with significant results, of other structures studied during the present SEM study, including the legs, opisthosoma, coxisternal plates and external genitalia, are possible.

3.2

MATERIAL AND METHODS

3.2.1

Low-temperature SEM

A modified version of the cryo-fixation technique described by Echlin et al. (1970) was used for preparing specimens for the present study using a conventional JEOL JSM 840 SEM with a cryostage. This stage is one of the first developed, and was modified by placing a cold trap on the specimen holder directly above the specimen (A. Hall, pers. comm.). The cryo-stages and -systems available today are technically more advanced and produce better results than the stage used for the present study (A. Hall, pers. comm.). Preparation procedures are presented here because they were developed for the SEM infrastructure available, and are not published, and may be of use in developing similar procedures by others who would like to use this technique.

Chapter 3. Morphology.

47

Fresh plant material preferably with live mites was used for study. Individual mites and mite colonies including eggs, spermatophores, etc. in situ on plant material, and later on in the study, single specimens collected from the material, were prepared and studied as follows:

The gum of one side of a piece of double-sided adhesive carbon tape small enough to fit in the hollow button (specimen holder) was exposed and this side stuck onto a transparency sheet.

The addition of the transparency sheet was necessary for manipulating the piece of carbon tape. The other side of the tape was also exposed. Tiny pieces of fresh plant material with as many live mites as possible on it (Fig. 3.7b), were arranged and stuck onto the exposed side of the tape (Fig. 3.7c). This was done with the aid of a dissecting stereo microscope. This procedure was not entirely satisfactory since many mites washed off during plunge-freezing in the nitrogen slush [Ebrahim et al., 1996; Craemer & Hall, 2003 (Appendix J.1.)]. The remaining mites were also not representing all positions necessary for a morphological study for systematic purposes. Most of them could only be viewed in dorsal view. The adaptation to the cold stage as described above limited its maneuverability, and the specimens could not be tilted, limiting the observation and capturing of images on different aspects of a single specimen. It was frequently difficult to find the mites on the plant material when viewed in the SEM (Fig. 3.7a). This technique was still used, though, to study the mites in situ in order to observe their ecology and biology, including eggs and spermatophores, and to study their morphology without any prior mechanical manipulation of the specimens which might alter or damage them.

Chapter 3. Morphology.

48

a b

The posterior, dorsal view of an individual of

Cecidodectes euzonus

among erineum on Trema

orientalis

abnormal hair growth (erineum) on the leaves of Trema orientalis egg shell individual mite of Aberoptus sp., probably adult, gender unknown eggs of the Aberoptus sp.

c d

individual, probably adult, of

Tergilatus sparsus on a piece of Portulacaria afra leaf; most other mites that were on the leaf when mounted, fell off when the specimen holder was plunged into the liquid nitrogen leaf stomatum holes in leaf caused by mechanical damage by tools when leaf was handled during the mounting process - the leaves of

Portulacaria are succulent, and the surface breaks easily.

adhesive carbon tape individual that walked onto the carbon tape during mounting process individual mites of Meyerella bicristatus (Meyer,

1989) from Mystroxylon aethiopicum mounted on adhesive carbon tape

Fig. 3.7. Unmodified SEM images: a) Specimens of Cecidodectes euzonus Nalepa, 1917 among erineum hairs caused by them on Trema orientalis, illustrating the difficulty to sometimes find the mites within complicated plant structures when viewed with SEM. This and the need to view them from different aspects, creates the need to mount them individually for systematic purposes; b) Individual of Aberoptus, probably new species, in situ on a Schotia brachypetala leaf - note the good turgor, with no apparent shape distortion, of both plant and mite material, including mite eggs; c) Tergilatus sparsus

Meyer & Ueckermann, 1995 on Portulacaria afra - a piece of plant material (leaf in this case) with live mites in situ, mounted on adhesive carbon tape; d) individual mites of Meyerella bicristatus (Meyer, 1989b) from Mystroxylon

aethiopicum stuck onto adhesive carbon tape to facilitate observation of different aspects of the mite specimens. The lengths represented by the scale lines are given below the lines.

Chapter 3. Morphology.

49

For these reasons, later on in the study, additional individual mites were taken off the plant material with an eyebrow hair mounted on a stick and mounted in the correct position on the carbon tape (Fig. 3.7d). After a specimen was mounted, it could not be moved again. Care was taken to mount live mites, and keep them alive through the mounting process to minimize distortion. The process of mounting the mites took about an hour, depending on the abundance and density of the mites and other factors. Unfortunately, the mites would still struggle after being put on the tape and in the process frequently damage themselves. This damage mostly involved the loss of limbs or attachments that could be identified as artefacts.

Even with the relative shallow surface of the carbon tape, some structures, such as empodia and setae of the specimens, sunk into the surface and were partly covered. Frequently, the existence of an assortment of species was only realized when the mites were studied in the

SEM.

When the piece of tape with plant material and mite specimens was ready, it was attached into a specimen holder with a sufficient amount of silver paint to earth the piece of tape. Hereafter the specimen holder was plunge-frozen in nitrogen slush. The holder with frozen specimens was then transferred via the pre-chamber of the cryo-system to the pre-cooled (about -170 °C) cryo-stage in the chamber of the SEM, where they were etched for ca. 30 minutes by increasing the temperature to ca. -80 °C to remove ice crystals. The completion of the etching was determined by observing a specific area of the material during the etching process. This was problematic because the specimen charged-up easily prior to sputter-coating. Ice was not always totally removed, or the specimens were rendered unstable by etching too extensively.

The specimen holder was then transferred back to the cryo-stage of the pre-chamber and sputter-coated with gold. Hereafter it was returned to the cryo-stage in the SEM for observation at an accelerating voltage of 5 kV, and sometimes 2 kV, to prolong viewing time.

This low current, particularly when using a conventional SEM, was also employed to alleviate charging and thereby increase resolution (A. Hall, pers. comm.).

The images were captured digitally in “.tiff” format employing a frame grabber controlled by

Orion

®

rel 6.6, Belgium (A. Hall, pers. comm.). These were cropped and edited with Corel Photopaint

®

Version 11.633. Obligatory text added by the SEM image-capturing system (image number, amount of accelerating voltage, etc.) (Fig. 3.7) was removed by cropping, or using the clone tool in Corel Photo-paint

®

, and the scale line was moved to a standardized position. Care was, however, taken not to alter any important image detail in the process. The images were laid out and labeled in Corel Draw

®

Version 11.633 or were inserted between text in Microsoft

®

Office

Chapter 3. Morphology.

50

Word 2003. Some SEM images were compared with either a light microscope study of the morphology of slide-mounted specimens or their published descriptions.

3.2.2

Specimens studied

The SEM study was planned to deal with species described from South Africa, and in particular newly described species and genera in order to use the SEM images in future for redescription of these species, and particularly the new genera. Mites were collected from the same host plants mostly at the same localities at which they were originally collected from. Mixtures of species, often including new species, were obtained from these collections. Since most of these may be difficult to obtain again, and to maximize available SEM time and to increase the variation of the morphology observed, they were included in the SEM study, although they restricted work time on targeted species. One collection of mites (Trisetacus sp. from Pinus pinaster in France) was also opportunistically studied to include representatives of this phytoptid genus, not present in South

Africa. About 3 500 SEM images of about 640 specimens of roughly 64 species (Table 3.1) were captured. This represents 23 genera of the 46 genera recorded from South Africa, including species of five [Afromerus Meyer, 1990 (Meyer, 1990b), Costarectus Meyer & Ueckermann, 1995

(Meyer & Ueckermann, 1995), Neserella Meyer & Ueckermann, 1989 (Meyer & Ueckermann,

1989b), Porosus Meyer & Ueckermann, 1995 (Meyer & Ueckermann, 1995) and Quintalitus

Meyer, 1989 (Meyer, 1989c)] of the nine genera described from South Africa. These genera might be endemic to the southern hemisphere, which are important in the context of the present study which focuses on taxa from this region, and in particular from South Africa. Despite efforts to do so, species of Adenocolus Meyer & Ueckermann, 1997 (Meyer & Ueckermann, 1997),

Aequsomatus

Meyer & Ueckermann, 1995 (Meyer & Ueckermann, 1995), Africus Meyer &

Ueckermann, 1995 (Meyer & Ueckermann, 1995) and Pyelotus Meyer, 1992 (Meyer, 1992c), all genera described from South Africa, could not be recollected during the study. Phyllocoptes sp. and Tetraspinus sp. were collected, and it is the first records of these genera from South Africa.

About 46 of the 64 species are probably undescribed and about six of these can be assigned to new genera.

3.2.3

Convention and use of morphological terminology in present study

The descriptions of morphological structures refer to only one half of the body, particularly in regard to the use of singular or plural, e.g., seta bv is present on leg I, and not setae bv are present on legs I, and seta sc is on or near the rear shield margin, and not setae sc are on or near the rear shield margin. Usually the abbreviation of structures, and particularly setae, are used, e.g., sc and not “seta sc”. These abbreviations are in brackets following the more complete names in Figs 3.2–

Chapter 3. Morphology.

51

3.6, 3.19, 3.20, 3.23. The following are exceptions to this usage: the single, unpaired seta vi positioned on the dorso-median anterior prodorsum is referred to as single seta vi; the components of the prodorsal shield pattern refer to the entire surface of the prodorsum (refer to both sides of the body). The length, or related terms, of a structure, is always parallel to the long axis of the body, and width is perpendicular to the long axis of the body; these orientations in appendages are according to the long axis of the particular appendage, except the conventional use of “dorsal annuli are broader or wider than the ventral annuli”, in stead of “dorsal annuli are longer than ventral annuli”.

Chapter 3. Morphology.

52

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

Mite species and higher classification Host plant species from which collected Mite habit and habitat Location collected Date collected, collector Date(s) studied with SEM

PHYTOPTIDAE

Phytoptidae: Nalepellinae: Trisetacini

Trisetacus sp. cf . T. pinastri Nuzzaci, 1975 Pinus pinaster Aiton (Pinaceae) colonies underneath bracts near collar of conelets and on conelets, no obvious symptoms detected

France, Lavercantiére (44°32'N, 1°19'E), and

Sivaillan

(45°03'N, 0°45'W)

2 June 2002; A. Rocque 04 June 2002

06 June 2002

07 June 2002

10 June 2002

Phytoptidae: Nalepellinae: Nalepellini

Setoptus radiatae Meyer, 1991 Pinus radiata D.Don (Pinaceae) between needles under needle sheaths 16 June 2003; S. Neser 18 June 2003 Mpumalanga Province, Sabie, Long Tom

Educational Centre

(24°13'S, 30°27'E)

Phytoptidae: Sierraphytoptinae: Mackiellini

Mackiella sp.

Eriophyidae: Cecidophyinae: Colomerini

Afromerus sp. cf . Afromerus lindquisti Meyer, 1990

Phoenix reclinata Jacq. Senegal (Arecaceae)

ERIOPHYIDAE

Eriophyidae: Aberoptinae

Aberoptus sp. nov.?

Aberoptus sp. cf . A. platessoides Meyer, 1989 (from Ochna sp.) or

Aberoptus sp. nov.? (from Schotia sp.)

Ochna pretoriensis E.Phillips (Ochnaceae) or Schotia

brachypetala Sond. (Fabaceae) (both prepared for SEM this day)

Aberoptus sp. nov.?

Schotia brachypetala Sond. (Fabaceae)

Schotia brachypetala Sond. (Fabaceae) colonies underneath spinned nests on leaf undersurfaces underneath spinned or waxy nests spinning, determine of which species the SEM images were taken colonies underneath spinned nests on leaf undersurfaces

Gauteng Province, Pretoria, ARC-PPRI

Vredehuis terrain nr. Union Building

(25°45'S, 28°12'E)

Gauteng Province, Pretoria

Grid Reference for central Pretoria:

(25°44'S, 28°12'E)

Gauteng Province, Pretoria, ARC-PPRI

Vredehuis terrain nr. Union Building

(25°45'S, 28°12'E)

Cecidophyopsis sp. cf . C. hendersoni (Keifer, 1954)

? 2003; S. Neser (NF2596)

S. Neser

19 February 2003; C. Craemer

Yucca guatemalensis Baker (Agavaceae)

(parts of cultivated plants from unknown nursery in Pretoria, submitted to ARC-PPRI for determining the "pathogen" causing the symptoms actually caused by the eriophyoid mites) colonies among small papilla-like erineum on both leaf surfaces caused by the mites as above Yucca guatemalensis Baker (Agavaceae)

(in door potted cultivated plant inoculated with Cecidophyes colonies from above material)

Yucca guatemalensis Baker (Agavaceae)

(in door potted cultivated plant inoculated with Cecidophyes colonies from above material) as above as above as above

Gauteng Province, Pretoria, unknown nursery

Grid Reference for central Pretoria:

(25°44'S, 28°12'E)

2 November 2001; C. Craemer

Gauteng Province, Pretoria, Montanapark X1,

Darter Street 1009

(25°45'S, 28°12'E)

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E)

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station

(25°43'S, 28°14'E)

22 January 2002; C. Craemer

24 January 2002; C. Craemer

18 July 2002; C. Craemer

Psydrax livida (Hiern) Bridson (Rubiaceae) worm-like vagrants in grooves underneath brown wiry tissue towards leave bases

Gauteng Province, Pretoria, northern border of National Botanical Garden

(25°44'S, 28°16'E)

13 May 2003; S. Neser

Ectomerus sp. cf . Ectomerus systenus Meyer, 1990

Neserella sp. cf. N. tremae

Terminalia sericea Burch. ex DC (Combretaceae)

Trema orientalis (L.) Blume (Celtidaceae)

15 May 2003

05 February 2003

10 February 2003

19 February 2003

15 November 2001

22 January 2002

24 January 2002

18 July 2002 white, worm-like mites in elongated leaf galls Gauteng Province, Pretoria, Meiring Naude

Road, nr. CSIR

(25°47'S, 28°17'E)

15 March 2002; S. Neser whitish mites in leaf galls (not fruit galls) Gauteng Province, Hartbeespoort, nr.

Saartjiesnek

(25°46'S, 27°56'E) white-yellowish leaf vagrants on leaf undersurfaces, no in erineum patches on leaves

Gauteng Province, Magaliesberg, Tonquani

Kloof, nr. Buffelspoort

(25°50'S, 27°29'E)

20 March 2003; S. Neser

27 July 2003; S. Neser (NF2622)

18 January 2003; S. Neser

(NF2593)

26 March 2002

28 March 2002

30 July 2003

23 January 2003

28 January 2003

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

Eriophyidae: Eriophyinae: Aceriini

Acalitus mallyi (Tucker, 1926) Vangueria infausta Burch. subsp. infausta (Rubiaceae) in leaf galls no collection record; S. Neser

(probably nr. Pretoria, South Africa)

Grid Reference for central Pretoria:

((25°44'S, 28°12'E))

Brazilia, nr. Palmeiras no collection record; S. Neser 22 May 2003

Aceria lantanae (Cook, 1909)

Aceria lantanae (Cook, 1909)

Aceria ocellatum Meyer & Ueckermann, 1990

Aceria sp. cf . A. dichrostachyia (Tucker, 1926) (check spelling of species name)

Aceria sp. cf. A. giraffae Meyer, 1990 (numerous yellow-orangey mites)

Aceria sp. cf. A. neseri Meyer, 1981

Aceria sp. cf . A. neseri Meyer, 1981

Aceria sp. cf . A. proteae Meyer, 1981

Aceria sp. nov. (in preparation)

Aceria sp. nov. (in preparation) (“new” seta on gnathosoma) unknown species, must still be identified, and it should be determined whether it is the same Aceria sp. of 16 April and 24 April 2002

Lantana x camara L. (hybrid complex) (Verbenaceae)

(material decomposed and mouldy)

Lantana x camara L. (hybrid complex) (Verbenaceae)

Rhus lancea L.f. (Anacardiaceae)

Dichrostachys cinerea (L.) Wight & Arn. subsp. and var. unknown

(Fabaceae)

Acacia erioloba E.Mey. (Fabaceae)

Chrysanthemoides incana (Burm.f.) Norl. (Asteraceae)

Chrysanthemoides monilifera (L.) Norl. subsp. monilifera

(Asteraceae)

Protea caffra Meisn. subsp. caffra (Proteaceae)

Ipomoea batatas (L.) Lam. var. batatas (Convolvulaceae)

Oxalis corniculata L. (Oxalidaceae)

Acacia sp. cf. A. rehmanniana Acacia rehmanniana Schinz

(Fabaceae) leaf galls flower galls Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station, Quarantine Glass House

(25°43'S, 28°14'E) date?; S. Neser

2 October 2002; C. Craemer

23 April 2002

03 October 2002 in relatively small, round leaf galls Gauteng Province, Pretoria, University of

Pretoria Campus

(25°14'S, 28°11'E)

27 August 2003, P. & C. Craemer

18 December 2001; C. Craemer

28 August 2003

18 December 2001

13 February 2002; C. Craemer

28 February 2002; C. Craemer

18 March 2002; C. Craemer

16 March 2003; S. Neser

13 February 2002

28 February 2002

18 March 2002

19 March 2003 deformed, clustered leaflets (no galls or outgrowths from Gauteng Province, Pretoria, Wonderboom leaflet surfaces) Fort, Northern slope

(25°39'S, 28°13'E) vagrant amongst the indumentum of very young podlets Northern Cape Province, Strydenburg

(29°56'S, 23°39'E) in brown erineum patches Western Cape Province, Clifton, Round

House Road

(33°56'S, 18°23'E) among fine erineum hairs in erineum patches (most mites already dead on plant material before cryo preparation) in erineum patches

Western Cape Province, Stellenbosch, Jan

Marais Park

(33°56'S, 18°51'E)

Western Cape Province, Stellenbosch, Jan

Marais Park

(33°56'S, 18°51'E) witches’ broom erineum and distortion distortion, thickening and leaf edge rolling leaf galls?

6 January 2002; S. Neser

20 February 2002; T. Morley

8 May 2002; T. Morley

20 May 2002; A. Wood (for S.

Neser)

Gauteng Province, Magaliesberg, Tonquani

Kloof, nr. Buffelspoort

(25°50'S, 27°29'E)

18 January 2003; S. Neser

South Africa, Mpumalanga Province, close to the border with Mocambique

(very broadly - exact location unknown)

February 2002; R.W. Gibson

Gauteng Province, Pretoria, Montanapark X1, 25 November 2001; C. Craemer

Darter Street 1009

(25°45'S, 28°12'E)

18 December 2001; C. Craemer

20 March 2003

24 January 2002

28 February 2002

09 May 2002

22 May 2002

5 June 2002; A. Wood (for S. Neser) 07 June 2002

29 January 2003

18 March 2002

26 November 2001

18 December 2001

28 March 2002

Aceria sp.? Acacia rehmanniana Schinz (Fabaceae) leaf galls

Aceria sp.? Cineraria sp. cf. C. lobata, or near (Asteraceae) blisters

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station, Quarantine Glass House, cultivated plant

(25°43'S, 28°14'E) date; S. Neser

Mpumalanga Province, Graskop, Pinnacle

Rock

Grid reference for Graskop:

(24°56'S, 30°50'E)

23 April 2002; A. Witt & S. Neser

2 September 2002; S. Neser

(NF2590)

16 April 2002

24 April 2002

12 September 2002

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

unknown species (eriophyinae-like mite) seems to be the same species (Aceria sp. nov.(?)) from Apodytes on 28 May but don’t identify for now due to host uncertainty

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae) (flowers) cultivated tree in garden

OR Mystroxylon (erineum)

Gauteng Province, Pretoria, Lynnwood Glen

(25°46'S, 28°17'E)

26 May 2002; S. Neser 27 May 2002

Aceria sp.? 26 May 2002; S. Neser 28 May 2002

Aceria sp. nov.?

Aceria sp. nov.?

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae) cultivated tree in garden among flower buds, and between leaf axils and axil buds Gauteng Province, Pretoria, Lynnwood Glen

(25°46'S, 28°17'E)

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae) one of two species on this material: this one worm-like and whitish, the other orangey = Phyllocoptinae?

Xymalos monospora (Harv.) Baill. (Monimiaceae) in growth points

Gauteng Province, Pretoria, Meintjieskop, behind Union Building

(25°44'S, 28°13'E)

Mpumalanga Province, Graskop, Pinnacle

Rock

Grid reference for Graskop:

(24°56'S, 30°50'E)

22 July 2003; S. Neser & C.

Craemer

2 September 2002; S. Neser

(NF2586)

23 July 2003

12 September 2002

Eriophyidae: Phyllocoptinae: Acaricalini

Tumescoptes sp. cf . T. dicrus Meyer, 1992

Eriophyidae: Phyllocoptinae: Calacarini

Calacarus sp.

Calacarus sp.?

Calacarus sp.?

Eriophyidae: Phyllocoptinae: Tegonotini

Shevtchenkella sp. cf . S. lividae (Meyer, 1990)

Shevtchenkella sp. cf . S. rothmanniae (Meyer, 1990)

Shevtchenkella sp. cf. S. rhusi (Meyer, 1990)

Neoshevtchenkella or Shevtchenkella sp.?

Eriophyidae: Phyllocoptinae: Phyllocoptini

Calepitrimerus sp.?

Cecidodectes euzonus Nalepa, 1917

Phyllocoptes sp.?

Phoenix reclinata Jacq. (Arecaceae) vagrant on green lamina Gauteng Province, Pretoria, northern border of National Botanical Garden

(25°44'S, 28°16'E)

13 May 2003; S. Neser

Rhus lancea L.f. (Anacardiaceae)

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae)

Psydrax livida (Hiern) Bridson (Rubiaceae) large number of purple leaf vagrants with white "stripes" or ridges

Gauteng Province, Pretoria, University of

Pretoria Campus

(25°14'S, 28°11'E) leaf vagrant, SEM of only one specimen

18 April 2002; C. Craemer

23 April 2002; C. Craemer

Mpumalanga Province, Long Tom Pass picnic 2 April 2003; A. Witt spot (25°08’S, 30°45’E), elevation 1 379m purple leaf vagrants with white "stripes" or ridges on mostly leaf upper surfaces

Gauteng Province, Pretoria, Meiring Naude

Road, nr. CSIR

(25°47'S, 28°17'E)

15 March 2002; S. Neser

15 May 2003

18 April 2002

23 April 2002

10 April 2003

26 March 2002

Psydrax livida (Hiern) Bridson (Rubiaceae)

Rothmannia capensis Thunb. (Rubiaceae)

Rhus lancea L.f. (Anacardiaceae)

Celtis africana Burm. f. (Celtidaceae)

(collected for pink vagrant with rows of lamellae on back (pers. comm., S. Neser)) orangey vagrants on leaf undersurfaces Gauteng Province, Pretoria, Meiring Naude

Road, nr. CSIR

(25°47'S, 28°17'E) orange mites mostly in hairy gland cavities, sometimes on leaf surfaces

Gauteng Province, Pretoria, National

Botanical Garden

(25°44'S, 28°16'E) vagrant Gauteng Province, Pretoria, University of

Pretoria Campus

(25°14'S, 28°11'E)

15 March 2002; S. Neser

14 August 2003; S. Neser & C.

Craemer

18 March 2002; C. Craemer leaf vagrants with wax structures

26 March 2002

15 August 2003

18 March 2002

23 April 2002; C. Craemer 23 April 2002

6 February 2003; S. Neser (NF2598) 10 February 2003 Gauteng Province, Pretoria, ARC-PPRI

Vredehuis terrain nr. Union Building

(25°45'S, 28°12'E)

Celtis africana Burm. f. (Celtidaceae)

(collected for pink vagrant with rows of lamellae on back (pers. comm., S. Neser))

Trema orientalis (L.) Blume (Celtidaceae)

Anthocleista grandiflora Gilg (Gentianaceae) leaf vagrant (species "B" and "C") very long (some shorter) smooth, pink-orange mites, only in erineum leaf vagrant

Gauteng Province, Pretoria, ARC-PPRI

Vredehuis terrain nr. Union Building

(25°45'S, 28°12'E)

Gauteng Province, Magaliesberg, Tonquani

Kloof, nr. Buffelspoort

(25°50'S, 27°29'E)

6 February 2003; S. Neser (NF2598) 12 February 2003

18 January 2003; S. Neser

(NF2593)

23 January 2003

Limpopo Province, Tzaneen

(23°50'S, 30°09'E)

A. Witt

28 January 2003

26 February 2003

05 March 2003

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

Tergilatus sparsus Meyer & Ueckermann, 1995 Portulacaria afra Jacq. (“(L.) Jacq.” according to GRIN)

(Portulacaceae)

(potted plant outdoors) leaf vagrant (one of possibly two species on this material: other “species” could be immatures of T. sparsus)

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E)

7 April 2002; S. Neser 08 April 2002

12 May 2002; C. Craemer 13 May 2002

Eriophyidae: Phyllocoptinae: Anthocoptini

Aculops or Metaculus sp.?

Aculus sp.?

Aculus sp.?

Aculus sp.?

Costarectus zeyheri Meyer & Ueckermann, 1995

Meyerella bicristatus (Meyer, 1989) new genus? near Costarectus new genus? near Tetra new genus? near Mesalox new genus? near Mesalox new genus? near Mesalox

Porosus monosporae Meyer & Ueckermann, 1995

Anthocleista grandiflora Gilg (Gentianaceae)

Aculus sp. cf . Aculops lycopersici (Tryon, 1917) (according to the definition of Aculus and Aculops by Amrine, Aculops lycopersici resorts in Aculus )

Physalis peruviana (Solanaceae)

Acacia burkei Benth. (Fabaceae)

Lantana trifolia L. (Verbenaceae)

Rothmannia capensis Thunb. (Rubiaceae)

Dovyalis zeyheri (Sond.) Warb. (Flacourtiaceae)

Mystroxylon aethiopicum (Thunb.) Loes. subsp. aethiopicum

(Celastraceae)

Mystroxylon aethiopicum (Thunb.) Loes. subsp. aethiopicum

(Celastraceae)

Protea caffra Meisn. subsp. caffra (Proteaceae)

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae)

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae)

(cultivated tree in garden) vagrant among flower buds

Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae) orangey and more scarce

Xymalos monospora (Harv.) Baill. (Monimiaceae) leaf vagrant, one specimen (without wax) leaf vagrant leaf vagrant without wax discolouration, slight distortion, retarded growth; large numbers of mites on leaves surrounding growth point, appearing like “pink powder” to the naked eye

Limpopo Province, Tzaneen

(23°50'S, 30°09'E)

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E)

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E)

Gauteng Province, Pretoria, Rietondale,

Soutpansberg Road, ARC-PPRI Research

Station, glass house,

(25°43'S, 28°14'E)

A. Witt

3 December 2002, C. Craemer

7 May 2003; S. Neser

25 September 2002; S. Neser

26 February 2003

04 December 2002

11 June 2003

25 September 2002 mites with wax, mostly in gland cavities, sometimes on leaf surfaces

Gauteng Province, Pretoria, National

Botanical Garden

(25°44'S, 28°16'E) light orange vagrants with white wax stripes on undersurface of leaves

North West Province, Magaliesberg, Dome

Kloof, nr. Buffelspoort

(25°50'S, 27°32'E)

North West Province, Magaliesberg, Castle

Gorge

(25°48'S, 27°34'E) mites with humps or large lobes dorsally on opisthosoma, sometimes dense colonies among hairs on young growth (30 April 2003) pinkish vagrant with wax ridges

14 August 2003; S. Neser & C.

Craemer

21 July 2002; S. Neser (NF2581)

3 August 2003; S. Neser (NF2633)

Gauteng Province, Pretoria, Lynnwood Glen,

Argyle Street or near

(25°46'S, 28°17'E)

19 May 2002; S. Neser

Gauteng Province, Pretoria, Lynnwood Road

(25°46'S, 28°16'E)

26 May 2002; S. Neser

30 April 2003; S. Neser

30 April 2003; S. Neser

July 2003, C. Craemer

15 August 2003

24 July 2002

13 August 2003

20 May 2002

27 May 2002

30 April 2003

07 May 2003

30 July 2003 undersurface of younger leaves

Gauteng Province, Pretoria, Lynnwood Glen

(25°46'S, 28°17'E)

26 May 2002; S. Neser

Gauteng Province, Pretoria, Meintjieskop, behind Union Building

(25°44'S, 28°13'E)

Mpumalanga Province, Bridal Veil Falls nr.

Sabie

(25°06'S, 30°47'E)

16 June 2003; S. Neser

29 January 2003

13 May 2002

27 May 2002

23 July 2003

18 June 2003

Quantalitus squamosus Meyer, 1989 Rothmannia capensis Thunb. (Rubiaceae)

30 June 2003

15 August 2003

Tegolophus sp. cf . T. orientalis Meyer, 1990

Tetra retusa Meyer, 1992

Trema orientalis (L.) Blume (Celtidaceae)

Bauhinia galpinii N.E.Br. (Fabaceae) probably white, worm-like colonies in bullae white-yellowish mites vagrant on podlets and on leaf uppersurfaces, particularly against main vein in closely folded leaves

Gauteng Province, Pretoria, National

Botanical Garden

(25°44'S, 28°16'E)

Gauteng Province, Magaliesberg, Tonquani

Kloof, nr. Buffelspoort

(25°50'S, 27°29'E)

14 August 2003; S. Neser & C.

Craemer

18 January 2003; S. Neser

(NF2593)

Gauteng Province, Pretoria, Montanapark X1,

Darter Street 1009

18 June 2002; C. Craemer

(25°45'S, 28°12'E)

23 January 2003

18 June 2002

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

Tetra or Tetraspinus sp.?

Chrysanthemoides monilifera (L.) Norl. subsp. monilifera

(Asteraceae) vagrant (all specimens dead on material before cryo preparation)

Western Cape Province, Stellenbosch, Jan

Marais Park

(33°56'S, 18°51'E)

20 June 2002; C. Craemer

20 May 2002; A. Wood (for S.

Neser)

20 June 2002

22 May 2002

Tetraspinus sp.?

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae) orange vagrants on leaf undersurfaces Mpumalanga Province, Long Tom Pass picnic 2 April 2003; A. Witt spot (25°08’S, 30°45’E), elevation 1 379m

09 April 2003

Tetraspinus sp.? (one of five? species: orange mites (may have two vagrant species in these SEM images – compare with 9 April))

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae) vagrant on leaf undersurfaces Mpumalanga Province, Long Tom Pass picnic 2 April 2003; A. Witt spot (25°08’S, 30°45’E), elevation 1 379m

10 April 2003

Tetraspinus sp.? (one of five? species: orange mites (may have two vagrant species in these SEM images – compare with 9 April))

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae) add images from description Unknown Unknown 22 August 2003

Eriophyidae: Phyllocoptinae (tribe uncertain)

Anthocoptini?: Aculus sp.?

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae) vagrant on leaf undersurfaces (possibly orange mite, not Tetraspinus nor Metaculus )

Mpumalanga Province, Long Tom Pass picnic 2 April 2003; A. Witt spot (25°08’S, 30°45’E), elevation 1 379m

09 April 2003

Eriophyidae (subfamily uncertain)

unknown species, possibly in Aceriini

Eriophyinae?: Aceriini?

Phyllocoptinae?

new genus? in Phyllocoptinae or Cecidophyinae

Phyllocoptes ? sp. (Phyllocoptinae: Phyllocoptini) (or may be a new genus in the Cecidophyinae) new genus? (subfamily uncertain)

Eriophyidae (not Neserella or Cecidodectes ) Eriophyidae (can not identify further but possibly Cecidophyinae: Colomerini: Circases )

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae)

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae)

(“Faurea galpinii ” with smooth leaves (pers. comm., S. Neser)

Ekebergia capensis Sparrm. (Meliaceae)

Acacia burkei Benth. (Fabaceae)

Dovyalis zeyheri (Sond.) Warb. (Falcourtiaceae)

Cussonia sp. (Araliaceae)

Trema orientalis (L.) Blume (Celtidaceae) single worm-like mites in hairs, between young flowers and axil buds of leaves

Mpumalanga Province, Long Tom Pass picnic spot (25°08’S, 30°45’E) (elevation 1 379 m)

2 April 2003; A. Witt 16 April 2003 second unknown species (worm-like), SEM images “B” Mpumalanga Province, Graskop, Pinnacle

Rock

Grid reference for Graskop:

(24°56'S, 30°50'E)

Gauteng Province, unknown location on distorted leaves (found only one dead specimen on material) vagrants with white wax ridges on leaf undersurfaces Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E) translucent white to dark puplish mites (not Tetra

zeyheri , probably new species) colonies especially along veins, and in large "nests" and colonies in elongated galls with necrosis in vein axils

North West Province, Magaliesberg, Dome

Kloof, nr. Buffelspoort

(25°50'S, 27°32'E) among and in flowers shorter white mites, only from erineum; dorsal view of one specimen only

North West Province, Magaliesberg, Castle

Gorge

(25°48'S, 27°34'E)

Unknown

Gauteng Province, Magaliesberg, Tonquani

Kloof, nr. Buffelspoort

(25°50'S, 27°29'E)

S. Neser (NF2589)

April 2002; N. Basson

7 May 2003; S. Neser

21 July 2002; S. Neser (NF2581)

Unknown - S. Neser

18 January 2003; S. Neser

(NF2593)

12 September 2002

16 April 2002 (01-02)

11 June 2003

24 July 2002

3 August 2003; S. Neser (NF2633) 13 August 2003

12 February 2003

28 January 2003

DIPTILOMIOPIDAE

Diptilomiopidae: Diptilomiopinae

Diptilomiopus apobrevis sp. nov. (description in preparation) Apodytes dimidiata E.Mey. ex Arn. (“E.Mey. ex Bernh.” according to GRIM) subsp. dimidiata (Icacinaceae) leaf vagrant add images from description

20 August 2003

Diptilomiopus faurius sp. nov. (description in preparation) Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae) add images from description

Mpumalanga Province, Nelspruit, Lowveld

National Botanical Gardens

(25°28'S, 30°59'E)

Arné

Mpumalanga Province, Long Tom Pass picnic 2 April 2003; A. Witt spot

(25°08’S, 30°45’E)

09 April 2003

Diptilomiopinae, unknown species Xymalos monospora (Harv.) Baill. (Monimiaceae)

10 April 2003

22 August 2003

18 June 2003 vagrant on undersurfaces of slightly younger leaves Mpumalanga Province, Bridal Veil Falls nr.

Sabie

(25°06'S, 30°47'E)

16 June 2003; S. Neser

30 June 2003

Table 3.1. List of eriophyoid species studied in the scanning electron microscope (SEM) study. Scientific names (and synonyms where given) of plant host species according to Germishuizen & Meyer (2003). Localities are in South Africa, except where otherwise given. Mite families, subfamilies and tribes in table arranged according to Amrine et al. (2003), the mite genera and species names are arranged alphabetically. Host plant names are followed by the plant family in brackets.

new genus? nr. Dacundiopus Mystroxylon aethiopicum (Thunb.) Loes. subsp. aethiopicum

(Celastraceae) vagrant scarcely distributed on leaves Gauteng Province, Pretoria, Lynnwood Glen,

Argyle Street or near

(25°46'S, 28°17'E)

7 April 2002; S. Neser 08 April 2002

15 April 2002; S. Neser

19 May 2002; S. Neser

Gauteng Province, Pretoria, Lynnwood Road

(25°46'S, 28°16'E)

30 April 2003; S. Neser

16 April 2002

20 May 2002

30 April 2003

Rhynacus sp.?

Dovyalis zeyheri (Sond.) Warb. (Falcourtiaceae) shiny, light orange-amber-cream vagrants on leaf undersurfaces

North West Province, Magaliesberg, Castle

Gorge

(25°48'S, 27°34'E)

6 May 2003; S. Neser 07 May 2003

3 August 2003; S. Neser (NF2633) 13 August 2003

ERIOPHYOIDEA (family uncertain)

gen. nov. unknown and unplaced species

Eriophyidae?: Phyllocoptinae: Anthocoptini?: close to Tetra ?

morphospecies one (family uncertain) morphospecies two (family uncertain)

Eriophyoidea

Eriophyoidea (one specimen)

Eriophyoidea

Rhus lancea L.f. (Anacardiaceae)

Faurea rochetiana (A.Rich.) Chiov. ex Pic.Serm. (Proteaceae)

(“Faurea galpinii ” with smooth leaves (pers. comm., S. Neser))

Anthocleista grandiflora Gilg (Gentianaceae)

Anthocleista grandiflora Gilg (floribunda?) (Gentianaceae)

Psydrax livida (Hiern) Bridson (Rubiaceae)

Rhus lancea L.f. (Anacardiaceae) or Lantana camara L.

(Verbenaceae) (plant material used this day)

Sideroxylon inerme L. subsp. inerme (Sapotaceae) in leaf blisters vagrant, SEM images of only one specimen, SEM images "B"

Gauteng Province, Pretoria, Soutpansberg

Road, ARC-PPRI Rietondale Research

Station,

(25°43'S, 28°14'E)

Mpumalanga Province, Graskop, Pinnacle

Rock

Grid reference for Graskop:

(24°56'S, 30°50'E) vagrant with wax structures on leaf undersurface, SEM of one specimen

Limpopo Province, Tzaneen

(23°50'S, 30°09'E)

7 November 2001; C. Craemer

S. Neser (NF2589)

A. Witt

08 November 2001

12 September 2002

26 February 2003 on green fruit Sabie, bottom of Long Tom-pass, about 5 km from Hazeyview (25°03'S,30°59'E), 1342 m above sea level

14 August 2003; S. Neser or A. Witt? 28 August 2003 white vagrants with wax on leaf undersurfaces, SEM image of one specimen in dorsal view, identificaiton not possible

Gauteng Province, Pretoria, Meiring Naude

Road, nr. CSIR

(25°47'S, 28°17'E) unknown one specimen, two SEM images

Lantana camara , Brazilia, S. Neser;

Rhus lancea , University of Pretoria Campus,

Pretoria

(25°14'S, 28°11'E)

15 March 2002; S. Neser

Lantana camara , Brasil, S. Neser;

Rhus lancea , University of Pretoria

Campus, Pretoria; C. Craemer

26 March 2002

23 April 2002 in open cup galls with white and brown erineum Western Cape Province, Hermanus

(34°25'S, 19°15'E)

1 February 2003; J.H. Giliomee 05 February 2003

PART I: GENERAL OVERVIEW OF THE CONTRIBUTION OF THE SEM

STUDY TOWARDS THE SYSTEMATIC MORPHOLOGY OF THE

ERIOPHYOIDEA

1

The present SEM study contributed new and improved information towards the systematics of the species for which adequate images could be captured. Some examples are presented here in a general overview and, therefore, all structures that may be of systematic value are not dealt with, or indicated in this part. A comprehensive comparative study of the gnathosoma is presented in

Part II.

3.3

PART I: RESULTS AND DISCUSSION

3.3.1

Comparison between SEM images and slide-mounted specimens

Some of the minute morphological structures of eriophyoid mites cannot be seen, or not clearly seen, when studying slide-mounted specimens using light microscopy. The resolution and study of these ultra-small and some larger features are significantly improved when utilizing SEM.

• Spinules and other structures on legs

Minute structures, with variation that may be of systematic value, are present on eriophyoid legs.

Some of these are visible with light microscopy, but typically may be difficult or impossible to describe or quantify accurately, and are not utilized in the systematics of the Eriophyoidea. Some descriptive drawings of eriophyoid species include spinules (spicules) (small, spine-like cuticular processes according to Walter, 2008) and other structures on the legs (e.g., De Lillo, 1988b: 18,

Fig. 4; Keifer, 1953: 74, Fig. 221), but these are not included in most descriptions, even if they may be present. Amrine et al. (1994) noted that numerous spinules can be seen on the lateral and distal margins of the femora and distal margins of the genua and tibiae in the SEM images of

Cecidophyopsis grossulariae

, but that these are difficult to observe with light microscopy.

Lindquist (1996a) noted that various spine-like projections or serrations can occur on the legs, but that the smaller of these are probably more generally present than indicated in descriptions.

1

Note that most of the comparisons and critique on observations from slide-mounted material, quality of slide-mounting, and descriptions thereof, entail the work of M.K.P. (Smith) Meyer and/or E.A. Ueckermann from South Africa. This is because the material included in the study was collected in South Africa, and the aim was to collect material that has already been described for comparison. The critique is not brought about by the quality of the taxonomic research of the Eriophyoidea by M.K.P. (Smith) Meyer and/or E.A.

Ueckermann. Their work is regarded as representing some of the better quality descriptions published on

Eriophyoidea in the world, and is only arguably surpassed in some aspects (more detail, and better mounting of specimens) by a few other eriophyoid taxonomists.

Chapter 3. Morphology.

59

Similar spinules were broadly quantified in the present study. Spinules were present in some species (e.g., indicated by open triangles on legs I and II of cf. Calacarus sp. from Psydrax livida,

Figs 3.8h, i) on congruent leg segment margins of different species. Sometimes these spinules are absent: there are for instance no appreciable spinules visible in the aspects viewed, between the femur and genu in specimens of Trisetacus sp. and Afromerus sp. (solid white arrows in Figs 3.8a and d, respectively). When these spinules are present on this margin (solid white arrows in Figs

3.8c, e-l), they broadly differ in size, position and number between species. For example, most spinules on this margin are probably present in the unknown species depicted in Fig. 3.8e.

Apart from these small structures, other characteristics, including shape and morphometrics of leg segments, and the position and shape of leg setae, can also be investigated for useful systematic information, and some of these are discussed here. The margin visible on the surface of the division between the femur and genu varies dorsally in the degree of fusion (solid white arrows in

Fig. 3.8). The femur and genu are fused in Diptilomiopus sp. (Fig. 3.8b), partly fused dorsally in

Trisetacus

sp., Afromerus sp., Acalitus mallyi and two Aceria spp. (Figs 3.8a, d, j, k and l, respectively), while separated in the remainder of the species (Figs 3.8c, e, f, g, and h). Various types of ornamentation may be present on the femur (black arrows in Fig. 3.8), for example, ridges on the femora of leg I in Cecidophyopsis sp. and Calacarus sp. (Figs 3.8c and h, respectively), and granules on the femur of the unknown species (Fig. 3.8e). These three species are vagrants, living exposed. The shape of the leg segments also vary between species. In particular, the tibiae (open arrows in Fig. 3.8) are more rounded without sharp edges and ridges in Trisetacus sp., Afromerus sp., Acalitus mallyi and Aceria sp. on Acacia rehmanniana (Figs 3.8a, d, j and k, respectively).

The tibiae of Diptilomiopus sp., Aculus sp., Calacarus sp. and Aceria sp. on Ipomoea batatas (Figs

3.8b, f, h, i, and l) have more straight and angular sides and ribs on the edge corners to varying degrees.

Chapter 3. Morphology.

60

a b d c e

genu and femur fused, but margin between these two segments would probably have been in this region artifact: ice crystals, caused by exposure of specimen to air humidity, of which remnants remained that were not removed by heating of material dirt on specimen artifact: cracking of surface caused by disintegration of biological material after a prolonged period in the SEM.

seta ending bluntly distally, could be natural, or artifact caused by preparation of material

Fig. 3.8. (continued on next page) Dorsal views of legs of: a) Trisetacus sp. (Phytoptidae: Nalepellinae: Trisetacini), bud mite on Pinus pinaster; b) Diptilomiopus faurius sp. nov. (Diptilomiopidae: Diptilomiopinae), leaf vagrant on Faurea

rochetiana; c) Cecidophyopsis sp. (Eriophyidae: Cecidophyinae: Cecidophyini), leaf vagrant on Yucca guatemalensis, d)

Afromerus sp. (Eriophyidae: Cecidophyinae: Colomerini), leaf galls on Psydrax livida, (the fine cracks are artificial, caused by deterioration of specimen in SEM); e) unknown family (Eriophyoidea), vagrant on green fruit of Anthocleista

grandiflora. Solid white arrows: dorsal completeness of margin between femur and genu on leg I, and presence, position and number of spines on this margin; solid black arrows: ornamentation on femur of leg I; open arrows: shape of tibia of leg I; a, b, c, d) scale lines = 10

µm; e) scale line = 1 µm.

Chapter 3. Morphology.

61

f h j l g i k

Fig. 3.8. (continued from previous page) f, g) Aculus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini), vagrant on

Lantana trifolia; h) leg I and i) leg II of cf. Calacarus sp. (Eriophyidae: Phyllocoptinae: Calacarini), leaf vagrant on

Psydrax livida; j) Acalitus mallyi (Eriophyidae: Eriophyinae: Aceriini), leaf galls on Vangueria infausta subsp. infausta;

k) cf. Aceria sp. (Eriophyidae: Eriophyinae: Aceriini), leaf galls on Acacia rehmanniana; l) Aceria sp. (Eriophyidae:

Eriophyinae: Aceriini), erineum and distortion on Ipomoea batatas var. batatas. Solid white arrows: dorsal completeness of margin between femur and genu on leg I, and presence, position and number of spines on this margin; solid black arrows: ornamentation on femur of leg I; open arrows: shape of tibia on leg I; open white triangles: segment margins on which spicules are present; f, h, j, l) scale lines = 10

µm; g, i, k) scale lines = 1 µm.

Chapter 3. Morphology.

62

It seems that in species living in less exposed situations such as in buds and galls, the margin between the femur and genu is partly fused with no or a few slight spinules, they have little or no ornamentation on the legs, and the tibiae are more smoothly rounded. In vagrant species living in more exposed situations, the margin between the femur and genu is complete and with spinules, and some species have ornamentation on some leg segments, and the tibiae are more angular with ribs. This extrapolation is preliminary, though, because so few species were studied.

A pattern of ridges ventrally on particularly the femur of leg I of Diptilomiopus faurius sp. nov. from Faurea rochetiana is another example of structures clearly visible in the SEM images (Fig.

3.9a), but hardly visible in slide-mounted specimens, which are represented by a realistic line drawing (Fig. 3.9b).

b a

Fig. 3.9. Diptilomiopus faurius sp. nov. from Faurea rochetiana (Appendix M), ventral view of leg I, with a pattern of ridges, a) clearly visible in the SEM images, but, b) barely visible in the slide-mounted specimens. This descriptive drawing was drawn from the specimen with the most complete visibility of these ridges. Scale line = 1 µm.

• Leg tarsus: empodium

The Eriophyoidea do not have paired true claws on the leg tarsi – they only have one empodium, the empodial “featherclaw”, on each (Lindquist, 1996a). The empodium is generally about 5 – 7

µ m long, and some of its features cannot be studied using light microscopy.

The number of empodial rays is frequently used to separate species, although there may be intraspecific variation. It is usually possible to count them on slide-mounted specimens using phase contrast light microscopy, but in some groups it is difficult to count the number accurately. For example, the accurate counting of the number of empodial rays in Diptilomiopus from slidemounted specimens is problematic, due to the empodial rays diagonally folding-in underneath the stem of each branch (Fig. 3.10a). This might be the reason why the number of empodial rays was not included in descriptions of Diptilomiopus spp. by A. Chandrapatya and/or J. Boczek, for

Chapter 3. Morphology.

63

example, D. aglaiae (Chandrapatya & Boczek, 2002a), and D. barringtoniae (Boczek &

Chandrapatya, 1992b). In some of these problematic cases, SEM studies may contribute this information. For example, eight rays are visible on each sub-branch of the divided empodium of

D.

faurius sp. nov. (Appendix M) collected from Faurea rochetiana (Fig. 3.10b).

a b

Fig. 3.10. Empodium on tarsus of leg I of Diptilomiopus faurius sp. nov. (Appendix M) from Faurea rochetiana: a) dorsal view depicting shape, b) lateral view facilitating count of rays – eight in this species.

Systematically informative characters which are not currently studied or recorded, mainly because they are not readily visible when studying slide-mounted specimens with light microscopy, may be found in the fine morphology of the empodium. The number of sub-rays and other small attachments to the main rays are difficult and frequently nearly impossible to detect or describe using light microscopy (Fig. 3.11). The numbers of sub-rays counted from the most distal ray for the first four species (a, b, c, d) in Fig. 3.11 are presented in Table 3.2. Before comparing this information for use in phylogenetic analyses, the homologies between specific rays must be established. Three scenarios may be possible for the development of added rays on the empodium: added at 1) the proximal end, 2) between the distal and proximal end, and 3) at the distal end.

Because the distal rays do not have sub-rays, unlike those more proximally, it is here proposed that the rays are added or lost basally (see Table 3.2), but it can possibly also be added centrally, for example, see Table 3.3.

Chapter 3. Morphology.

64

ray 6 ray 5 ray 4 ray 3 ray 2 ray 1 ray 5 ray 4 ray 3 ray 2 ray 1

Table 3.2. Number of sub-rays present on the most distal main ray to the basal or proximal ray (numbered as they are present in the 7-rayed Trisetacus sp.), when added rays develop proximally, in a Trisetacus sp. from Pinus pinaster (Fig.

3.11a), Cecidophyopsis sp. from Yucca guatemalensis (Fig. 3.11b), Shevtchenkella sp. from Psydrax livida (Fig. 3.11c) and an unknown species from Dovyalis (Fig. 3.11d).

Eriophyoid species Trisetacus sp. Cecidophyopsis sp. Shevtchenkella sp. Unknown sp. distal ray (ray 7) 0 ray 6 1

0

1

0

1

0

1/2

2

3

3/4

3

2

2

3

3

2

2

1

2

Table 3.3. Number of sub-rays present from the most distal main ray to the basal or proximal ray (numbered as they are present in the 7-rayed Trisetacus sp.), when added rays develop centrally, in a Trisetacus sp. from Pinus pinaster

(Fig. 3.11a), Cecidophyopsis sp. from Yucca guatemalensis (Fig. 3.11b), Shevtchenkella sp. from Psydrax livida (Fig.

3.11c) and an unknown species from Dovyalis (Fig. 3.11d).

Eriophyoid species Trisetacus sp. Cecidophyopsis sp. Shevtchenkella sp. Unknown sp. distal ray (ray 7) 0 0 0 0

1

2

2

3

3/4

3

3

3

1

2

2

1

2

1 2

1/2

Chapter 3. Morphology.

65

a

ray 2 with 3 sub-rays

(Table 3.2) empodium

c b d f e g h

Fig. 3.11. Distal parts of tarsi with focus on the empodia: a) Trisetacus sp. from Pinus pinaster; b)

Cecidophyopsis sp. from Yucca guatemalensis; c) Shevtchenkella sp. from Psydrax livida; d) unknown species from Dovyalis; e) unknown species from Faurea rochetiana; f) Acalitus mallyi; g) Aceria sp. from Ipomoea batatas; h) unknown species from Apodytes dimidiata. Scale lines = 1 µm.

Chapter 3. Morphology.

66

The shape of the empodium (simple or divided) is important in defining subfamilies (e.g.,

Diptilomiopinae and Rhyncaphytoptinae) and tribes (e.g., Diphytoptini of the Phyllocoptinae)

(Fig. 3.6, also see Lindquist, 1996a: 21). Other differences in more detailed shape may also occur, but have not been defined, and their visibility on slide-mounted species has not been recorded, but should be investigated. One example is the variation in the shape of the empodial rays. The rays of Acalitus mallyi (Fig. 3.11f) are flattened and the sub-rays are not clearly-defined, and the tips are not clearly tenent-like (the tips of tenent setae or seta-like processes are flattened perpendicularly to the longitudinal shaft of the ray, resembling the head of a nail), whereas the rays in other species, such as Shevtchenkella sp. (Fig. 3.11c), an unknown species from Faurea

rochetiana

(Fig. 3.11e), and a new genus from Apodytes dimidiata (Fig. 3.11h) are more rounded and end in tenent-like tips. The size of the enlarged and flattened membrane-like attachment (Fig.

3.13f) distally on the tenent-like empodial rays differs among species. It may be large and conspicuous in some species, such as in the unknown species from Dovyalis (Fig. 3.11d) and

c

sp. (Figs 3.7e, f), and small or possibly absent in others such as Trisetacus sp. (Fig.

3.11a), Acalitus mallyi (Fig. 3.11f) and Aceria sp. from Ipomoea batatas (Fig. 3.11g).

The empodial rays of Aceria sp. nov. from Ipomoea batatas (Fig. 3.11g) appear generally thin and fragile in comparison with the other species depicted here. These differences in shape are currently not used, but could possibly be used in eriophyoid systematics in future.

• Detailed morphology of structures included in descriptive drawings, and frequently used to differentiate species

Some structures, such as the fine detail of the prodorsal shield and coxisternal plate ornamentation, and the external genitalia and surrounding areas, can essentially not be described or drawn from slide-mounted specimens to depict the exact true morphology of living specimens. This is caused by the distortion of slide-mounted specimens, and the resolution and essentially two-dimensional view in one plane of light microscopy. SEM alleviates these problems by revealing the true shape, orientation and ornamentation of structures. It may also improve the comprehension of these structures, and hopefully serve as impetus to describe and draw them from slide-mounted specimens in more accurate detail.

A case study: The structure and ornamentation of the external female genitalia are frequently depicted simplified and schematically in eriophyoid descriptions (e.g., Fig. 3.12b). In the SEM image of the coverflap of Tergilatus sparsus (Fig. 3.12c) the area basal to (anteriad of) the longitudinal ribs, for example, is much broader and the shape of the area is different to that depicted in the drawing (Fig. 3.12b). The fine detail and exact three-dimensional structure cannot

Chapter 3. Morphology.

67

be seen in the slide-mounted specimen (Fig. 3.12a) due to inadequate clearing and staining of the specimen which can be rectified by improved slide-mounting, but also due to factors inherent to study of slide-mounted specimens using light microscopy already mentioned. Even with the slidemounted specimens at hand (e.g., Fig. 3.12a), the drawing can be rectified to depict the true morphology more closely, but never to the degree possible with the addition of information from a

SEM study. This is evident when published images and drawings are compared with SEM images of the same species. This inaccuracy of conventional eriophyoid descriptions renders the determination of primary homologies between specific areas impossible or ambiguous.

a b c

Fig. 3.12. External female genitalia of Tergilatus sparsus Meyer & Ueckermann, 1995 (Meyer & Ueckermann, 1995): a) a slide-mounted specimen (holotype) viewed with phase contrast; b) a drawing made from slide-mounted specimen; c)

SEM image of same area in another specimen. Drawing reproduced from the original unpublished drawing with permission from the authors.

Chapter 3. Morphology.

68

• Determining primary homologies between Eriophyoidea and other mite groups

Comparative studies of fine external morphology using SEM will aid in elucidating the similarity in structure, and primary homology between structures of Eriophyoidea and those of other mites, which is currently problematic. For example, studying the fine morphology of, and particularly of the tip of the empodial rays in the Eriophyoidea and homologous structures in other mite groups, will give better results when using SEM studies. Lindquist (1996a) hypothesizes that the empodial rays with enlarged tips in the Eriophyoidea are “equivalent to” (homologous to) the tenent hairs present in various superfamilies of trombidiform (including prostigmatid) mites. Several specimens of prostigmatid mites were included ad hoc in the present SEM study as they were encountered while collecting the eriophyoid mites. The morphology of the tenent hairs of

Tetranychidae, Tenuipalpidae and Stigmaeidae (Fig. 3.13) are roughly the same as the empodial rays of the Eriophyoidea in having an enlarged, frequently flattened tip, but there are some differences. The enlarged and flattened area is at the distal end of the seta (ray) in the other mites

(open arrows in Figs 3.13a, b, c), while in the Eriophyoidea, it is rather a thin, seemingly membrane-like attachment or enlargement behind the tip of the ray (or the tip of the ray extends beyond the enlargement) (Figs 3.13e, f). The empodium of a new genus from Apodytes dimidiata

(Fig. 3.13f) illustrates how the rays, and particularly the tips, are probably orientated when the empodium is resting on a surface. The empodial hairs of Tydeus sp. in the present study (Fig.

3.13d) are different from tenent hairs in not having a flattened tip apically, but rather a slight knob

[in spiders a similar type of hair and tip is also referred to as a “tenent hair” (A.S. Dippenaar-

Schoeman, pers. comm.)]. When compared with the empodial rays in eriophyoid species, the empodial hairs in Tydeus also differ by not having side branches. Therefore, although the empodium of Aberoptus sp. (Figs 3.13e, f) may be homologous to the Tydeus empodium in having a central stem or pad with numerous radiating rays, the rays of the two structures are not similar.

The level of detail in which the structures were studied in this example, is not possible when studying slide-mounted specimens with light microscopy.

Chapter 3. Morphology.

69

a c b d e f distal end of ray shaft above membrane

-like extension membrane-like extension lying flat (sucking action?) on substrate probably slight ridge-like extension of ray shaft to which membrane-like extension is attached membrane-like extension curled back over ray shaft elements when ray is not

“sucking” to substrate solenidion without visible longitudinal ribs, but may have ribs in other eriophyoid species membrane-like extension curled back over ray shaft elements when ray is not

“sucking” to substrate

Fig. 3.13. Ambulacra with tenent hairs: a) leg II of an Aponychus sp. (Tetranychidae) from Solanum mauritianum; b) leg

I of a species of the Tenuipalpidae from a Senecio sp.; c) leg I of a species of the Stigmaeidae from Apodytes dimidiata.

Empodia with slightly knobbed hairs or rays (Tydeus) and “tenent” hairs or rays (Aberoptus) of: d) leg I of cf. Tydeus sp.

(Tydeidae) from Ekebergia capensis Sparrm.; e, f) leg II of an Aberoptus sp. (Eriophyidae) from Schotia brachypetala; a,

c, f) scale lines = 10 µm; b, d, e) scale lines = 1 µm. Arrows pointing towards tips of hairs of rays, with an enlarged drawing of the tip of the ray of the empodium of the Aberoptus sp. in Fig. 3.13f.

Chapter 3. Morphology.

70

3.3.2

Artefacts caused by preparation and slide-mounting of specimens

Slide-mounted specimens have preparation / mounting artefacts varying in degree, and influence on the taxonomic process. The significance and number of artefacts caused will vary according to the technique used and the quality of and the way in which the process is done, and the influence of the person’s experience and skill. Every batch processed may vary in the exact treatment and result from other batches. Artefacts are thus not standardized and comparable across specimens mounted in different batches. For example, rib-like ornamentation may still be present in specimens, but absent in specimens on another series of slides. This causes even more confusion.

Examples of artefacts caused by slide-mounting are here discussed and illustrated with examples from the SEM study.

• Loss and/or distortion of fine-detail such as microtubercles, and ridges on annuli and legs

The clearing process for slide-mounting of eriophyoid mites may destroy fine external structures to various degrees, either by eroding them or “stretching” the cuticle, smoothing them out. Even in the final mounting fluid, clearing may continue. This is particularly prevalent when slides are stored in collections for extended periods. Over time, the specimens may become lighter and loose definition, until some of the structures vanishes, making the specimens unusable for systematic study (De Lillo et al., 2010). Various other factors influence the visibility of fine-structures in slide-mounted specimens, including the amount of staining of specimens, the distance and amount of mounting fluid between specimens and the cover-slip and the quality of the microscope used and the ability of the observer (De Lillo et al., 2010).

Chapter 3. Morphology.

71

d g h a b c e f i

Fig. 3.14. Microtubercles of Aceria sp. nov. from Ipomoea batatas: dorsally on first annuli behind the prodorsal shield rear margin - a, b) SEM images, d) line drawing; dorsally on rear caudal annuli - c) SEM image, f) line drawing; on ventral annuli between setae e - g) line drawing, h) SEM image; on rear, caudal ventral annuli - e) line drawing, i) SEM image; all scale lines = 10 µm except h) scale line = 1 µm.

Chapter 3. Morphology.

72

The presence, shape, size and position of microtubercles and small granules or other ornamentation on the eriophyoid body are extensively used in the differentiation of eriophyoid taxa, particularly at species level. Microtubercles are extremely small, and resolution is not always satisfactory with light microscopy and necessitates the improvement of resolution provided by

SEM (Fig. 3.14). Iodine, added to the preparatory and mounting media, may help to make such fine, shallow and vague structures more visible by colouring them (De Lillo et al., 2010; J.W.

Amrine, Jr., pers. comm.). Three-dimensional images provided by SEM in contrast to slidemounted specimens where one may only be able to view these very small structures in one twodimensional plane instead of more planes possible through larger structures, improves their study the most. The microtubercles may also be distorted and displaced during the slide mounting process. Another problem that may occur with slide-mounted specimens is that some microtubercles are extremely small and fine and their presence and shape may be obscured by a heavily sclerotized cuticle (J.W. Amrine, Jr., pers. comm.). The improvement provided by SEM to study microtubercles in their natural shape and position can be seen when the line drawings of slide-mounted specimens and SEM images of the same areas of the same species in Fig. 3.14, are compared.

Another example of an artefact caused by slide-mounting is the obliteration of fine ridges on the body surface. Fine striae or ridges are present on the dorsal lobes and annuli of Meyerella

bicristatus

(Meyer, 1989) and can be clearly seen in SEM images of the species (Fig. 3.15a).

These ridges are essentially invisible in the slide-mounted specimens of the same species (Fig.

3.15b), either because they are so shallow and without colour differentiation that they cannot be discriminated from surrounding surfaces, or they may have been destroyed by the clearing or mounting process. The ridges are thus also absent from the descriptive drawing of the species

(Figs 3.15c). This character was used in the couplet descriptive states in the identification key to genera by Amrine et al. (2003) to differentiate Neophantacrus Mohanasundaram, 1981 in which the lobes are striated from Meyerella Amrine et al., 2003 in which the lobes are smooth. In this case, fortunately it does not influence the outcome of the key, because additionally there are three rows of lobes in Neophantacrus, and only two in Meyerella.

Chapter 3. Morphology.

73

a b c

Fig. 3.15. Meyerella bicristatus (Meyer, 1989), leaf vagrant on Mystroxylon aethiopicum subsp. aethiopicum: a) SEM image of dorso-lateral aspect (scale line = 10 µm); b) part of lateral aspect of slide-mounted specimen (female) viewed with phase contrast light microscopy; c) line drawing [reproduced with permission from the original drawing by Meyer

(1989b)] of the specimen digitally-imaged in 3.15b. Arrows indicating: ribs or striae on lobes in SEM image; striae very vaguely present in this one slide-mounted specimen of a series of about 100 specimens in which they were invisible (the lines are hardly visible in the printed copy, but when this image is enlarged on computer screen, the lines are vaguely visible); and the lobes are smooth in the descriptive drawing.

Chapter 3. Morphology.

74

• Distortion of body shape

The general shape and presence of depressions, ridges, furrows or other modifications of the basic rounded body form of genera such as Aceria are extensively used in eriophyoid classification, delimiting mostly genera, but also subfamilies and tribes (Amrine et al., 2003). The loss and distortion of shape, including body shape, are some of the more serious artefacts caused by slidemounting.

During the clearing process for slide-mounting, it is possible to see how the bodies of the specimens contract and expand alternately during the different collecting and clearing steps (pers.

obs

.). One would suspect that this should cause some distortion, but it has not been investigated.

When the specimens on the final mounting-slide are covered by a cover-slip, the specimens are flattened and squashed to varying degrees (De Lillo et al., 2010).

The shape of the slide-mounted specimens of Tergilatus sparsus Meyer & Ueckermann, 1995 (Fig.

3.16) is an example of serious shape distortion. In the lateral view of a slide-mounted specimen

(Fig. 3.16b), the body seems to be globose while in real life it is dorsoventrally flattened (Figs

3.16a, d). The shape of the body could have been seen by observing live specimens under a dissecting stereo microscope before mounting. Of more concern and importance, however, is the more subtle depression caudally behind the middorsal ridge visible in SEM (open white arrows in

Figs 3.16a, h) that is not visible in live or slide-mounted specimens studied with light microscopy

(open arrows in Figs 3.16c, g, i). The three-dimensional orientation of the broad ridge-like structure just posterior of the prodorsal rear shield margin (black arrows in Figs 3.16a, h, l) is not retained. This “collar” is flattened in the slide-mounted specimens (Figs 3.16b, j, k) and in the drawings thereof (Figs 3.16c, g). These artefacts in body shape may lead to wrong morphological information being built into the eriophyoid classification. It may be tolerated in the classification and identification of species in practical taxonomy, if the artefacts in slide-mounted specimens are standardized enough to avoid errors in identification using slide-mounted specimens. It is inappropriate data, however, for determining primary homologies for phylogenetic analyses.

Tergilatus sparsus

(Fig. 3.16) again illustrate the improved information regarding fine morphology obtained from SEM images in comparison with slide-mounted specimens and drawings thereof.

There is a rounded thickening at one end of the elongated microtubercles on the dorsal annuli (Fig.

3.16f) which are not clearly visible in slide-mounted specimens, and consequently this detail has not been included in the descriptive drawing (Fig. 3.16e). These ridges are also much finer in comparison to the size of the mite than what could be portrayed in the drawing. The intricacies of

Chapter 3. Morphology.

75

detail, shape and relative positions of structures on the ventral aspect (Fig. 3.16d) were not visible in such detail in the slide-mounted specimens.

• Loss of secreted structures, and their study

Secreted body layers of eriophyoid mites such as wax, may be lost during preparation of specimens for slide-mounting. Tetra retusa Meyer, 1992 was described by Meyer (1992b) (Fig.

3.17b) without depicting or mentioning the wax structures present on the species (Figs 3.17a, c, e).

Although the presence of wax on a species may be observed in live specimens before collection and mounting, using stereo dissection microscopy, it is not always clearly visible, even on live mites (pers. obs.). Studying the fine structure, shape and position of these secreted structures (Figs

3.17 a, c-e) and the external morphology of body parts possibly secreting the wax is by far superior using SEM.

3.3.3

Ecological and biological information

Finally, when studying the mites in situ with the low-temperature method, one has the added advantage of being able to study some aspects of the biology and ecology of the mites (Duffner et

al.

, 1998; Wergin et al., 2000; Ochoa et al., 2000). This includes studying the structure, position and other aspects of for example, their eggs and spermatophores. The shape, biology and ecology of spermatophores have been studied by a few authors (e.g., Oldfield et al., 1970; Sternlicht, 1970;

Sternlicht & Griffiths, 1974; Chandrapatya & Baker, 1986; Duffner et al., 1998). Oldfield et al.

(1970) speculated that the shape of the spermatophores may differ between species, and that it may have systematic value. The spermatophores of the possibly new Aculus sp. from Lantana trifolia

(Figs 3.18a, b), and eggs and immatures of an unidentified species, probably a Rhynacus sp. (Fig.

3.18c) are examples of observations on in tact eriophyoid colonies in the present study. In the latter species, it was interesting to note how close together the eggs were laid, to the extent that they pressed against each other, changing their normally round shape slightly (Fig. 3.18c).

Biological and ecological information can also be investigated for their possible potential as systematic characters, and this information can also be used for phylogenetic studies.

Chapter 3. Morphology.

76

a b d c e f

Fig. 3.16. (continued on next page). Tergilatus sparsus Meyer & Ueckermann, 1995, leaf vagrant on Portulacaria afra:

SEM images (a, d, f, h, j), line drawings (c, d, g) [from Meyer & Ueckermann (1995)], and slide mounted specimens viewed with phase contrast (b, i, j, k): a) dorsal view; b, c) lateral view; d) ventral view; e, f) enlargement of opisthosomal microtubercles, alternatively lateral and dorsal; g, h) dorsal view; i) dorsal view of opisthosomal rear end; j, k, l) prodorsum (lateral in j, dorsal in k, l) including rear shield margin and first dorsal annuli; a, d, h, l) scale lines = 10 µm; f) scale line = 1 µm. Open arrows – rear end of opisthosoma; solid black arrows – first annulus behind rear prodorsal shield margin, black dashed arrow – pointing towards dorsal microtubercles in drawing and SEM image.

Chapter 3. Morphology.

77

g h i k l j

Fig. 3.16. (continued from previous page).

Chapter 3. Morphology.

78

a d b c c e

Fig. 3.17. Tetra retusa Meyer, 1992 from Bauhinia galpinii (Meyer, 1992b): a, c, e) wax secretions and enlargements thereof on about the entire body, but particularly on the ridges of the opisthosoma and prodorsal shield, all specimens in dorsal view; b) descriptive drawing (Meyer, 1992b) in dorsal view, without the wax, which was also not mentioned in the text description. Calacarus sp. from Searsia lancea (previously Rhus lancea): d) dorso-lateral aspect of the prodorsum with wax formations, the image of a specimen with some of the wax disturbed and broken off was chosen to be presented, to illustrate the inside and structure of wax cells; a, d, e) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

79

a

sperm packet attachment site from which the sperm packet has been removed

b

feeding punctures as result of eriophyoid mite feeding base of spermatophore stalk of spermatophore head of spermatophore sperm packet in place

c c

larva of eriophyoid species, probably Rhynacus sp.

collapsed spermatophore egg, pressed against other eggs larva of eriophyoid species, probably Rhynacus sp.

Fig. 3.18. Spermatophores of Aculus sp. from Lantana trifolia: a) with sperm packet in tact; b) without sperm packet.

Possibly Rhynacus sp. from Mystroxylon aethiopicum subsp. aethiopicum: c) eggs and immatures; scale line length representations given below scale lines. SEM images are unmodified.

Chapter 3. Morphology.

80

PART II. COMPARATIVE MORPHOLOGICAL STUDY OF THE

GNATHOSOMA USING SEM

2

3.4

PART II. INTRODUCTION

Understanding and knowing the structures and relative positions of the different structures of body parts to each other, are crucial in identifying, delimiting and comparing characters and character states in different taxa. Therefore, the structure and comparative morphology of the eriophyoid gnathosoma, and confusion in the use of terminology, are here briefly discussed.

The mouth-parts of the Arachnida typically comprise the labrum, mouth, in some taxa the socalled labium (the sternite of the palp segment), and the chelicerae and palpi (Evans, 1992).

In the

Ricinulei and Acari, construction of the pre-oral channel or chamber for food reception, involves the enlargement and ventral fusion or approximation of the palpcoxae and their apophyses to form a unit underneath the chelicerae. This unit is called the subcapitulum

(infracapitulum or hypognathum), incorporating the labrum, mouth and pharynx (Evans,

1992).

The subcapitulum, chelicerae and the free-moving parts of the palpi that are not incorporated in the subcapitulum, together form the gnathosoma (capitulum), a discrete, sensorytrophic movable structure (Evans, 1992) which is also present in the Eriophyoidea (Keifer, 1959a;

Nuzzaci & Alberti, 1996) (Figs 3.19, 3.20, 3.22).

Several different terms are used for the same gnathosomal structures of mites (De Lillo et al.,

2001) and likewise the terminology and fundamental understanding of the eriophyoid gnathosoma and the manner in which this information is used in taxon descriptions are not standard and are often used vaguely and arbitrarily. The same term frequently does not refer to the same structure.

For example, the term “rostrum”: Lindquist (1996a) remarked that the infracapitulum is also named the rostrum or hypostome in eriophyoid literature. The term rostrum is, however, also frequently used to denote the subcapitulum together with the chelicerae, or even to denote the entire gnathosoma. For example, in the same book where there is a chapter by Lindquist (1996a),

Lindquist & Amrine (1996) use gnathosoma and rostrum as synonyms, and similarly, Nuzzaci

(1979) uses capitulum and rostrum as synonyms. Keifer (1959a) stated that the mouth-parts of the eriophyoids are collectively named the rostrum, thus rostrum is an alternative term for gnathosoma. In the same article, however, when the gnathosoma is discussed, the subcapitulum is

2

Note that some duplication of information presented in the first part of the chapter occurs in this part, because it will be submitted as an article separate from the first part.

Chapter 3. Morphology.

81

regarded as the rostrum, and the chelicerae and palpi as separate entities in association with the

“rostrum”. Keifer (1975a) remarks that the rostrum of the Diptilomiopidae (called

Rhyncaphytoptidae by him) is always large in comparison to the body, implying that the chelicerae and oral stylet form part of the rostrum. Amrine et al. (1994) refer to the dorsal view of the gnathosoma in an SEM image as “paired palpi functioning as a rostrum”. These and similar inconsistencies in the terminology lead to misunderstanding of the morphology and the specific parts being described.

Studies on the eriophyoid gnathosoma (including, Nalepa, 1887, 1898b, 1910; Keifer, 1959a;

Orlob, 1966; Shevchenko & Silvere, 1968; Krantz, 1973; Gibson, 1974; McCoy & Albrigo, 1975;

Hislop & Jeppson, 1976; Nuzzaci, 1979; Thomsen, 1987, 1988; Freeman et al., 2005) were undertaken on a few species. These studies focused primarily on functional anatomy and morphology, feeding mechanisms, and salivary glands and their secretions. Lindquist (1996a),

Nuzzaci & Alberti (1996) and Nuzzaci & De Lillo (1991, 1996) reviewed the anatomy and morphology of the eriophyoid gnathosoma.

The eriophyoid gnathosoma is uniquely specialized for piercing plant cells and sucking their sap

(Lindquist & Oldfield, 1996). The dorsomedial surface of the subcapitulum has a longitudinal ushaped open channel or stylet sheath extending from the base to the apical end of the palpi (Keifer,

1959a; Shevchenko & Silvere, 1968; Nuzzaci, 1979; Lindquist, 1996a; Nuzzaci & Alberti, 1996;

Nuzzaci & De Lillo, 1996). This sheath encloses either seven (Thomsen, 1987) or nine (Nuzzaci &

Alberti, 1996; De Lillo et al., 2001) stylet-like structures. These include a pair of cheliceral stylets that may divide apically into two stylets (Shevchenko & Silvere, 1968; Lindquist, 1996a; Freeman

et al.

, 2005), an oral stylet (labrum), a pair of auxiliary stylets (Keifer, 1959a, 1975a), or inner infracapitular stylets (Nuzzaci & Alberti, 1996), and a pair of cheliceral guides (Keifer, 1959a,

1975a), or outer infracapitular stylets (Nuzzaci & Alberti, 1996) (Fig. 3.22a). The outer infracapitular stylets project freely in the Phytoptidae and Diptilomiopidae (Nuzzaci & Alberti,

1996). SEM studies by Thomsen (1987) and Freeman et al. (2005) confirmed or elucidated internal gnathosomal structures.

Chapter 3. Morphology.

82

Nuzzaci & De Lillo (1991) compared the anatomy of the eriophyoid gnathosoma with that of other phytophagous groups. Lindquist (1996a) homologized the gnathosomal structures used in eriophyoid taxonomy with those of other mites and named them accordingly. In comparison with the relatively simplified body of the Eriophyoidea, their gnathosoma is complex, and homologies of some of the structures with other mites are problematic (Shevchenko & Silvere, 1968;

Lindquist, 1996a, b; Lindquist & Oldfield, 1996; Nuzzaci & Alberti, 1996). Only a few studies

(e.g., Keifer, 1959a) focused specifically on comparative morphology for application in the systematics of the Eriophyoidea.

3.4.1

Gnathosomal characters currently used in eriophyoid taxonomy

• The two major gnathosomal forms

The most pertinent character, and one of the few hypothetical synapomorphies used in the classification of the Eriophyoidea (Lindquist, 1996b), is the presence of two fundamental forms of the cheliceral and oral stylets and associated structures differentiating the Diptilomiopidae (“bigbeaked” eriophyoids) from the other eriophyoid families (Keifer, 1959a, 1975a; Lindquist, 1996a)

(Figs 3.22a, b). In the Eriophyidae and Phytoptidae, the cheliceral stylets are slightly and evenly curved and relatively small to moderate in size and the oral stylet are of the so-called “short form” and mostly associated with a generally smaller and less robust gnathosoma than in the

Diptilomiopidae (Fig. 3.22a). The cheliceral stylets of the Diptilomiopidae are generally longer and more robust with an abrupt basal curvature, correlated with the “long form” oral stylet (Fig.

3.22b). These two major gnathosomal forms are easily discernible in slide-mounted specimens, particularly in lateral view (Figs 3.22a, b). They can even be distinguished in live specimens when using a very good quality stereo dissecting microscope with sufficient illumination and magnification (preferably x 100 magnification).

• Other gnathosomal characters

According to Lindquist (1996a), gnathosomal morphology, including the setation on and segmentation of the palpi, are relatively stable throughout the Eriophyoidea. Very few gnathosomal characters are currently used in eriophyoid taxon differentiation and classification, and identification keys. In practice very few of even these are constantly included in species descriptions.

Chapter 3. Morphology.

83

a free-moving parts of the palpi extension of palpcoxal base (sensu Lindquist, 1996a) b palp apical lip tarsus tibia palp seta d (palp d) is absent in this species, but when it is present, it occurs about in this position subcapitulum (stylet sheath) seta ep (ep) probably auxiliary stylet (inner infracapitular stylet) cheliceral stylet (fixed digit) cheliceral retainer frontal lobe trochanter-femur-genu palpcoxal base c palp apical lip seta v (v) tarsus tibia genu trochanter-femur d subcapitulum: cheliceral sheath subcapitulum: palpcoxal plate subcapitulum and parts of the palpcoxae, including those parts of the palpcoxae that are incorporated in the subcapitulum, and possibly also including coxisternal ellements

Fig. 3.19. Eriophyoid gnathosoma: a) dorsal view; b) line drawing of gnathosoma in image 3.19a; c) ventral view; d) line drawing of the gnathosoma in image 3.19c. Scale lines = 1

µm.

Chapter 3. Morphology.

84

a b seta d (palp d) palp trochanter-femur pedipalp genu seta v (v) lateral extension of stylet sheath* d leg trochanter c coxisternal plate I palp trochanter-femur stylet sheath of subcapitulum lateral extension of stylet sheath* palpcoxal collar* lateral palpcoxal area* species) palp-leg coxal connection* coxisternal region anterior part of leg coxa, not covered by coxisternal plate

Key to colours in Figs 3.20 and 3.21

- green: margin between palp genu (ventrally) or trochanter-femur-genu segment (dorsally) and the palp tibia

- light blue: margin between palp genu and trochanter-femur (only present ventrally)

- red: anterior outlines of stylet sheath, but only of visible parts in a particular view

- yellow: proximal (posterior) margin of the stylet sheath and lateral extension of the stylet sheath; the anterior

visible edge of the stylet sheath is red, and that of the lateral extension of the stylet sheath, black

- purple: outlines of the anterior part of the palpcoxal plate and the lateral palpcoxal area

- dark blue: margin between the leg coxa and leg trochanter

- orange: posterior (towards rear) edge of the palpcoxal plate, which is the margin between the palpcoxal plate

and the coxisternal area and also between the anterior part of the leg coxa and the coxisternal plate

- area between the posterior part of the palpcoxal plate and the coxisternal plates or coxisternal area is here named the

“palp-leg coxal connection” and is outlined anteriorly with purple, and posteriorly with orange

Fig. 3.20. (continued on next page). Gnathosoma of Calacarus sp. (Eriophyidae: Phyllocoptinae: Calacarini): a) ventral view; b) ventro-lateral view; c) line drawing of Fig. 3.20a; d) line drawing of Fig. 3.20b; a) scale line = 1 µm; b, c, d) scale lines = 10 µm. * These are preliminary new names or terms devised in the present study for these gnathosomal structures on the ventral aspect of eriophyoid mites. ** This structure was named the “basal palp segment” (Keifer, 1975a) or the “oral plate”. It is just ahead of the coxisternal plates of coxae I, and is situated about on the same vertical level as the pharyngeal pump (Krantz, 1973; own observations) and may include elements of the coxisternum.

Chapter 3. Morphology.

85

e f seta v (v) palp tarsus palp tibia palp genu palp trochanter-femur stylet sheath of subcapitulum g lateral palpcoxal area palpcoxal plate the palpcoxal collar and lateral extension of stylet sheath obliterated or covered by palpcoxal plate, and the palpcoxal plate may stretch across these areas in all natural positions of the gnathosoma h stylet sheath of subcapitulum palp genu palpcoxal collar lateral palpcoxal area seta v (v) palp-leg coxal connection anterior part of leg coxa palpcoxal plate (roundly elevated in this species)

Fig. 3.20. (continued from previous page). Eriophyoid gnathosomas in ventral view. Trisetacus sp. cf. T. pinastri Nuzzaci,

1975 (Phytoptidae: Nalepellinae: Trisetacini) from Pinus sp.: e) SEM image; f) line drawing of Fig. 3.20e.

Shevtchenkella sp. cf. S. lividae (Meyer, 1990) (Eriophyidae: Phyllocoptinae: Tegonotini) from Psydrax livida:g) SEM image; h) line drawing of Fig. 3.20g; e, f) scale lines = 10 µm; g, h) scale lines = 1 µm.

Chapter 3. Morphology.

86

palp genu stylet sheath of subcapitulum

Trisetacus sp. cf. T. pinastri

(Phytoptidae: Nalepellinae:

Trisetacini)

Setoptus radiatae

(Phytoptidae: Nalepellinae:

Nalepellini). Slightly distorted, but shape more elongated than in the other species in this figure.

Mackiella sp.

(Phytoptidae:

Sierraphytoptinae:

Mackiellini)

lateral extension of stylet sheath palpcoxal plate

Aberoptus sp. cf. Aberoptus sp. nov. (Eriophyidae:

Aberoptinae)

Aceria sp. cf. A. dichrostachyia

(Eriophyidae: Eriophyinae: Aceriini)

flap-like extension of the palpcoxal collar covering the stylet sheath and partially ventral parts of the palpi

Aceria sp. cf. A. giraffae

(Eriophyidae: Eriophyinae:

Aceriini)

Aceria sp. cf. A. neseri

(Eriophyidae: Eriophyinae:

Aceriini)

Acalitus mallyi (Eriophyidae:

Eriophyinae: Aceriini) unknown species (Eriophyidae) from

Sideroxylon inerme subsp. inerme unknown genus, cf. Aceria sp.

(Eriophyidae: Eriophyinae:

Aceriini) from Apodytes

dimidiata subsp. dimidiata

Fig. 3.21. Eriophyoid gnathosoma: Ventral views of largely the subcapitulum and part of the palpi and palpcoxal plate of various species to show the differences in structures. The shape of the ventral part of the stylet sheath is visible between the free palp-segments. Its shape is probably strongly influenced by the angle at which imaged, and the anteriad extension of the gnathosoma at the moment of cryo freezing. However, there are some obvious differences in shape not influenced by these factors, that may be of use in classification and phylogeny. The data were not evaluated and this figure purely demonstrates that there are indeed differences that may be of systematic use. The colours correspond to probably homologous areas between the species. The longer scale lines = 10 µm, and the three shortest scale lines = 1 µm.

Chapter 3. Morphology.

87

c a b d frontal lobe enlarged, bulb-like base of chelicera attached to the motivator cheliceral stylets – relatively short and straight (this shape present in the Phytoptidae and Eriophyidae) auxiliary stylets (inner infracapitular stylets) oral stylet hinge pharyngeal pump short form oral stylet outer infracapitular stylets frontal lobe oral stylet hinge pharyngeal pump long form oral stylet cheliceral and auxiliary stylets (cheliceral stylets relatively large, extending a short distance forward, then abruptly bending downwards) e

Fig. 3.22. Eriophyoid gnathosoma. The gnathosoma of all the Eriophyoidea except the Diptilomiopidae has relatively short and straight chelicerae, and the short form oral stylet: a) digital image of slide-mounted specimen viewed with light microscope; c) SEM image of lateral view. “Diptilomiopid”-like gnathosoma with large chelicerae sharply bent down at the base and the long form oral stylet: b) digital image of slide-mounted specimen, d, e) lateral views of gnathosomas.

Scale lines = 10 µm.

Chapter 3. Morphology.

88

a palpcoxal seta, seta ep (ep) palpcoxal base

(not a free segment) b trochanter-femur-genu according to Lindquist (1996a)

*

dorsal palp genual seta, seta d (palp d) palp apical lip subapical palp tarsal seta, seta v (v)

2

3

1 trochanter-femur*

(present study) subcapitulum cheliceral sheath subcapitulum

(palpcoxal plate) genu* (present study) tibia tarsus palp apical lip

2

3

1 subcapitulum

(palpcoxal plate) subapical palp tarsal seta, seta v (v) antapical seta palp apical lip or tarsus

4 ge

6?

sensory seta or papilla

5 fe

3 c d basal seta

2

2 troch troch proximal segment

(second palp segment)

(palp trochanter)

3 fe basal or first palp segment

(palp coxae)

1 intermediate palp segment

(third palp segment) basal or first palp segment

(palp coxae) fourth palp segment (longer in the

Diptilomiopidae than in other eriophyoids) three (if apical lip is a segment) (genu, tibia, tarsus) or two terminal segments

(genu, tibiotarsus?) (Keifer, 1959a)

4 ge

6

5 ta ti

1 two segments

(Keifer, 1975a) sensory seta or papilla on second last segment

Fig. 3.23. Different hypotheses regarding the homology of the pedipalpal segments of the Eriophyoidea with other

Acariform pedipalpi: a, b) segments according to Lindquist (1996a) (according to him palpi with three free segments), and present study, *according to Lindquist (1996a) the first free segment is a fusion of the trochanter, femur and genu, according to the present study, however, the genu is dorsally fused with the other segments, but ventrally separated from them; c) segments and terminology according to Keifer (1959a); d) segments and terminology according to Keifer

(1975a); terminology not used by Keifer (1959a, 1975a) but added to Figs. 3.32c, d to homologize with usual segment names: troch = trochanter, fe = femur, ge = genu, ti = tibia, ta = tarsus, tibiotarsus; 1, 2, 3, 4, 5 = numbers of free segments

(Lindquist, 1996a) or segments (Keifer, 1959a, 1975a) (to indicate number of segments according to each hypothesis [not included here: five segments according to Shevchenko & Silvere (1968)]). Scale lines = 10 µm.

Chapter 3. Morphology.

89

Characters that have been included in some published species descriptions to date are: i.

The angle at which the gnathosoma projects from the body is frequently described, especially in earlier descriptions such as “the rostrum is projecting down” in

Diptilomiopus jevremovici

(Keifer, 1960) and D. knorri (Keifer, 1974) and “rostrum curved downwards” in Acalitus mallyi (Tucker) (Meyer, 1990a). Generally, the eriophyoid gnathosoma has about a hypognathous orientation (directed ventrally) reducing the ventral surface. It is reported to be more prognathous (directed anteriorly) in the Phytoptidae and Eriophyidae (e.g., Figs 3.27c, 3.38c), and more hypognathous in the Diptilomiopidae (e.g., Fig. 3.79b), with many intermediates between these two positions (Nuzzaci & Alberti, 1996); ii.

The length of the gnathosoma and of the chelicerae is regularly recorded; iii.

The presence (or absence) and length of the palp setae, or some of the palp setae, are sometimes recorded. Mostly, these setae are not depicted in the descriptive drawings of the gnathosoma, even when recorded in the text description. Some attention is given to the shape of palp d, if it is different from the usual simple shape, for example, it is bifurcate in some species (e.g., in Tumescoptes sp., Fig. 3.47d; and in

Porosus monosporae

, Figs 3.68a-c); iv.

Amrine described the shape of the cheliceral retainer, and found it to be different between morphologically similar species (Amrine et al., 1994); and v.

In some species, such as Aceria pretoriensis (Meyer, 1989) (= Cisaberoptus

pretoriensis

Meyer, 1989), the apical ends of the palpi have triangular projections

(Meyer, 1989a).

In their guidelines for describing eriophyoid species, Amrine & Manson (1996: 384) suggested that the following gnathosomal characters should be included in descriptions: i. Length of the gnathosoma measured from the base of the chelicerae to the apical ii. palp ends;

Lengths of the palp ep, d and v (Figs 3.23a, b); and iii. Description of the shape and position of the cheliceral guide (refer to the definition, description of these structures below).

One of the problems in studying and incorporating gnathosomal characters from slide-mounted specimens is the quite severe “squashing” and deformation of the gnathosoma. Additionally, the

Chapter 3. Morphology.

90

“halo” created by phase-contrast light microscopy is particularly bad in this area due to the complex of stylets and other dense structures present.

Not much attention has been given to the morphology of the gnathosoma in the description of taxa, and particularly not the shape and relative position of structures. When the morphology of the gnathosoma is studied in more detail, however, using techniques such as the low-temperature SEM

(present study), it becomes apparent that very few of the potentially useful and available systematic characters are used.

3.4.2

Gnathosomal characters currently used in phylogenetic treatises

In comparison with the gnathosoma of many free-living acariform mites, there is loss or reduction in eriophyoid gnathosomal structures (Lindquist & Oldfield, 1996) as follows:

The ventral surface of the subcapitulum is reduced and lacks adoral and infracapitular setae;

The palpi are reduced in segmentation and lack most of the setae and the tarsal solenidion; and

The chelicerae are without setae, and the cheliceral bases are relatively small and do not form a stylophore which is present in, e.g., Tetranychidae.

Structures with similar form and function than most of the eriophyoid gnathosomal components are not found among other acariform mites (Lindquist, 1996a; Lindquist & Oldfield, 1996;

Nuzzaci & Alberti, 1996), apart from possible homologies postulated by Nuzzaci & de Lillo

(1991). In particular, the small, knob-like motivator between the cheliceral bases is unique to the eriophyoids (Shevchenko & Silvere, 1968; Lindquist & Oldfield, 1996).

Nuzzaci & De Lillo (1991) compared gnathosomal morphology and feeding mechanisms of phytophagous mite groups, and particularly the different structures constituting the gnathosoma, including the lateral labia, subcapitulum, labrum, chelicerae and feeding process. They largely studied them using TEM. Additional stylets and a cheliceral sheath are present in the

Eriophyoidea, and a salivary pump in the Tetranychidae and Tenuipalpidae. They could not find major differences between the families Tetranychidae and Tenuipalpidae, and similarly not between the three eriophyoid families, Eriophyidae, Phytoptidae and Diptilomiopidae, except the larger and more robust gnathosoma in the Diptilomiopidae. They identified three gnathosomal types, or three evolutionary lines, representing the Tetranychoidea, Penthaleidae and Eriophyoidea

(only taking into consideration the representative groups they studied). According to the

Chapter 3. Morphology.

91

characteristics they studied, they concluded that the Eriophyoidea and Penthaleidae are morphologically more similar to each other than both are to the Tetranychidae and Tenuipalpidae, and thus the Eriophyoidea and Penthaleidae may be more closely related than either is to the

Tetranychidae and Tenuipalpidae.

A comprehensive comparative morphological study of the gnathosomas of about 64 species studied with SEM (Table 3.1) is presented here (including Table 3.4), except seven species where the gnathosoma could not be studied sufficiently due to the frontal lobe obscuring the gnathosoma entirely, or where too few specimens were available or in the correct position: Shevtchenkella sp.

cf.

S. rothmanniae (Meyer, 1990); Quantalitus squamosus Meyer, 1989; unknown genus, possibly of the Anthocoptini, and specimens that could not be identified to family level, from Faurea

rochetiana

; unknown genus of the Eriophyidae from Trema orientalis; morphospecies one from

Anthocleista grandiflora

; and specimens that could not be identified to family level from Psydrax

livida

. The SEM images and some accompanying drawings are presented in Figs 3.25-3.85.

3.5

PART II: RESULTS AND DISCUSSION

3.5.1

Chelicerae

Only two characteristics of the chelicerae are currently used in eriophyoid taxonomy: the length of the chelicerae, and the two general shapes differentiating the Diptilomiopidae from the remainder of the Eriophyoidea (Fig. 3.22, and see above for more detail). However, other characteristics of the chelicerae may be useful for systematics. One such character is the division of the cheliceral shaft into a dorsal and ventral digit or filament, proposed to be modified from the fixed and movable cheliceral digits, respectively, as in some of the species investigated in previous studies

(Shevchenko & Silvere, 1968; Krantz, 1973; Keifer, 1975a; Nuzzaci, 1979; Thomsen, 1987;

Freeman et al., 2005). The lower, thinner digit seems to be articulated to the upper digit in an

SEM image presented by Freeman et al. (2005). It is unknown whether the cheliceral shaft is divided in all eriophyoid species (Lindquist, 1996a), but may be of use if it is present or absent in some groups, or may vary in other respects. This character can only be observed using TEM

(Nuzzaci & Alberti, 1996) and where the internal stylets are sufficiently exposed in SEM studies

(e.g., Thomsen, 1987; Freeman et al., 2005) or in slide-mounted specimens (Krantz, 1973). In slide-mounted specimens, it is more difficult to detect because the two digits may lie very close together, appearing as one undivided stylet or the lower digits or filaments may be thin and fragile and obscured by other gnathosomal structures.

Chapter 3. Morphology.

92

Table 3.4. New potentially useful gnathosomal characters for systematics. Character states were scored from SEM images (Figs 3.25-3.85). char = character; cs = protuberances (possibly papillae, setae or spines) proximally on the chelicerae; approximation = dorsal approximation of pedipalp coxal base segment edges; ep orientation = orientation of seta ep in relation to the palp surface; ep direction = anteriad direction of seta ep ; ep position = distance of seta ep from palpcoxal base segment distal margin; ep r-position = relative position of seta ep on basal segment (basal segment length / distance of seta ep from distal margin); stylet elevation = elevation of chelicerae and other stylets above palpi at about level of proximal margin; ? = unknown (could not be determined, or scored state uncertain).

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment

Char 4 Char 5 Char 6 Char 7 Char 8 Char 9

Fig.

3.25

Mite species and classification

PHYTOPTIDAE

Nalepellinae: Trisetacini

Trisetacus sp. cf . T. pinastri from Pinus pinaster

Nalepellinae: Nalepellini cs

? (may be covered by palpi)

approximation

& shape

touching; curved

length

ep

orientation ep direction

10.6 appressed parallel

ep

position

5.5

ep

rposition ridges or depressions

1.9 no ridges

ornamentation (other than ridges)

unornamented

?

touching; straight

20.0 erect?

parallel 18.8

1.1

longitudinal ridge along the extended inside margin of ep terminating in an ovalish depression, margined with a slight ridge, distally (Fig. 2a) unornamented

3.26

3.27

Setoptus radiatae

from Pinus radiata

Sierraphytoptinae: Mackiellini

Mackiella sp. from Phoenix reclinata

ERIOPHYIDAE

Aberoptinae

?

?

? ?

?

?

?

?

ridge on the outer side of the enlarged cheliceral bases and insertion of

ep , causing these structures to be enclosed in a hollow with ep inserted

1.9

on vertical edges (Fig. 4a) unornamented

3.28

Aberoptus sp. cf . Aberoptus sp. nov.

from Schotia brachypetala

Cecidophyinae: Cecidophyini

absent separated; straight, parallel

7.5 erect medially 4.0

3.29

3.30

3.31

3.32

3.33

3.34

3.37

3.38

3.39

3.40

3.41

3.42

3.43

3.44

Cecidophyopsis sp. cf. C. hendersoni from Yucca guatemalensis

Cecidophyinae: Colomerini

Afromerus lindquisti

from Psydrax livida

Ectomerus sp. cf . E. systenus from Terminalia sericea

Neserella sp. cf. N. tremae from Trema orientalis

Eriophyinae: Aceriini

Acalitus mallyi

from Vangueria infausta subsp. infausta

Aceria lantanae (flower gall race) from Lantana x camara (hybrid complex)

Aceria ocellatum

from Searsia lancea present in immature, could not be determined in adult absent

?

absent absent present touching; straight separated; curved separated; slightly curved separated; curved separated; slightly curved separated; curved

11.2 erect

5.0 erect

4.0 erect

2.7 erect

6.8 appressed

7.0 erect medially medially converging converging parallel parallel

8.1

2.8

2.2

1.3

3.0

3.2

3.35

3.36

3.45

absent separated; curved 4.8 appressed converging 2.5

Aceria sp. cf. A. dichrostachyia from Dichrostachys cinerea subsp. and var. unknown absent or very slight

Aceria sp. cf. A. giraffae from Acacia erioloba

Aceria sp. cf . Aceria sp. nov.

present absent separated; slightly curved separated?

separated from Chrysanthemoides incana

Aceria cf. Aceria sp. nov. from C. monilifera subsp. monilifera

Aceria sp. cf. A. proteae absent separated separated; absent or very slight straight?

from Protea caffra subsp. caffra

Aceria sp. cf. Aceria sp. nov. from Ipomoea batatas var. batatas

Aceria sp. cf . Aceria sp. nov. present separated present separated from Oxalis corniculata

Aceria sp. cf. Aceria sp. nov. from Acacia rehmanniana

Unknown genus, nr. Aceria from Apodytes dimidiata subsp. dimidiata

cf. Aceria sp. from Cineraria sp.

present?

present absent?

separated separated; straight?

separated

4.6 erect

7.0 appressed

6.5 erect

6.7 erect

8.0 appressed

6.0 erect

7.0 erect

6.4 erect

6.4 appressed

? (too slanted) erect parallel converging parallel?

parallel?

converging parallel parallel parallel converging

2.3

3.6

2.8

2.8

4.8

3.6

3.6

3.0

3.4

parallel ? (too slanted)

1.4

ridge extending in a half circle from seta ep to the proximal margin on the outer side of the palpcoxal base; setae ep inserted in relatively vertical palp edges, causing the setae to project medially

1.8 no ridges

1.8 no ridges

2.0 no ridges

2.3 no ridges

2.2 no ridges

1.9 no ridges

2.0

strong ridge running to outside from seta ep , forking; strong diagonal ridge from below ep to distal coxal base margin (Fig. 12a)

2.0 slight ridge running from seta ep diagonally to outside

1.7 possibly very slight ridge running to outside from seta ep

1.7 possibly very slight ridge running to outside from seta ep

2.0 no ridges

2.1 no ridges

1.9 no ridges

? possibly very slight ridge running to outside from seta ep unornamented unornamented unornamented unornamented unornamented unornamented unornamented unornamented unornamented

2.3 two slight parallel ridges antaxially of seta ep , forming a slight trough unornamented two tubercles close to proximal

2.4 two slight parallel ridges antaxially of seta ep , forming a slight trough margin?

unornamented unornamented unornamented unornamented unornamented unornamented

?

Fig.

Mite species and classification

3.46

3.47

3.48

3.49

3.50

3.51

3.52

3.53

3.54

3.55

3.56

3.57

3.58

Aceria sp. cf. Aceria sp. nov. from Xymalos monospora

Phyllocoptinae: Acaricalini

Tumescoptes sp. cf. T. dicrus from Phoenix reclinata

Phyllocoptinae: Calacarini

Calacarus sp. from Searsia lancea

Calacarus sp. from Faurea rochetiana

Calacarus sp. from Psydrax livida

Phyllocoptinae: Tegonotini

Shevtchenkella sp. cf. S. lividae from Psydrax livida

Shevtchenkella sp. cf . S. rhusi from Rhus lancea

?

present?

?

?

absent?

absent?

?

Neoshevtchenkella or Shevtchenkella sp. (with wax) from Celtis africana

Phyllocoptinae: Phyllocoptini

cf. Calepitrimerus sp.

from Celtis africana

Cecidodectes euzonus

from Trema orientalis

cf. Phyllocoptes sp. from Anthocleista grandiflora

Tergilatus sparsus

from Portulacaria afra

Phyllocoptinae: Anthocoptini

Aculops or Metaculus sp. from Anthocleista grandiflora absent?

present absent present present absent?

3.59

3.60

3.61

Aculus sp. cf . Aculops lycopersici from Physalis peruviana

cf. Aculus sp. from Acacia burkei

cf. Aculus sp. from Lantana trifolia

3.62

3.63

3.64

3.65

3.66

3.67

3.68

3.69

3.70

cf. Aculus sp. or possibly immature of Quantalitus from Rothmannia capensis

Costarectus zeyheri

from Dovyalis zeyheri

Meyerella bicristatus

from Mystroxylon aethiopicum possibly a new genus nr. Costarectus from Mystroxylon aethiopicum possibly a new genus nr. Tetra from Protea caffra subsp. caffra possibly a new genus nr. Mesalox from Apodytes dimidiata

Porosus monosporae

from Xymalos monospora

Tegolophus sp. cf. T. orientalis from Trema orientalis

Tetra retusa

from Bauhinia galpinii present present present

?

?

present present

?

present

?

?

present

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment cs approximation

& shape length

separated separated separated?

separated?

separated

Char 4

5.5 (lateral) erect

? erect

? erect

? erect

? erect

Char 5

ep

orientation ep direction

Char 6

ep

position

Char 7 Char 8

ep

rposition ridges or depressions

Char 9 ornamentation (other than ridges)

tubercles or granula particularly in area distally of insertion of seta ep from anterior to lateral region (Fig.

22b) converging2.8 (lateral)2 (lateral) no ridges converging?

?

?

9.4 (lateral) parallel? 11.0 (lateral) converging8.9 (lateral)

? possibly no ridges possibly unornamented

?

ridge extending in a half circle from seta ep to the proximal margin on the outer side of the palpcoxal base ridge extending in a half circle from seta ep to the proximal margin on

?

the outer side of the palpcoxal base ridge extending in a half circle from seta ep to the proximal margin on

?

the outer side of the palpcoxal base unornamented unornamented unornamented separated separated?

separated?

separated?

separated separated separated separated separated separated?

separated separated?

separated?

separated separated?

separated?

separated

?

separated?

separated

? erect

? erect

? erect

? erect

7 (lateral) erect

? erect

? erect

? erect

7.9 erect

? erect

6.3 erect

? erect

? erect

6.0 erect

? erect

? ?

9.4 (lateral) erect

? ?

? erect

5.5 erect converging4.1 (lateral) parallel converging converging4.3 (lateral) parallel?

3.4 (lateral) converging converging?

converging parallel?

converging

?

?

?

? no ridges?

? no ridges?

? no ridges?

unornamented?

unornamented?

unornamented?

? no ridges?

unornamented?

2.0 no ridges granulated ridge diagonally downwards from seta ep (similar to this

?

ridge in other species) (Fig. 33a) transverse ridge proximally on palpcoxal base in immature, presence

?

not determined in adult unornamented granulated (Fig. 33a) unornamented

4.5

3.7

?

3.3

? no ridges?

ridge extending in a half circle from seta ep to the proximal margin on

2.1

the outer side of the palpcoxal base, more vague and larger circle than those in Calacarus spp.

unornamented?

unornamented

? half circular ridge running diagonally on outside of ep unornamented

1.9 slight ridge running from seta ep diagonally to outside few slight granules converging?

converging

?

?

converging6.1 (lateral)

?

?

converging converging

?

3.0

?

4.0

? single lobe like ridge on the outside of seta ep

? single vertical lobe like ridge antaxially of seta ep unornamented unornamented

1.5 no ridges unornamented

? no ridges

?

probably a lobe like vertical ridge on the outside edge of a diagonal ridge running from ep backwards

1.5

no ridges or possibly very slight ovalish area diagonally on coxal base demarcated by very slight ridges, barely visibly unornamented unornamented unornamented

? ?

? no ridges?

1.8 single diagonal ridge from ep to distal margin of palp coxal base

?

unornamented?

unornamented

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment cs approximation

& shape length

Fig.

Mite species and classification

3.71

3.72

3.73

3.74

3.75

3.76

3.77

Tetraspinus sp. from Chrysanthemoides monilifera subsp. monilifera present

cf. Tetraspinus sp. from Faurea rochetiana present

Eriophyidae (subfamily uncertain)

possibly new worm-like genus (Eriophyinae?:

Aceriini?) from Faurea rochetiana unknown genus (Phyllocoptinae?) from Ekebergia capensis possibly a new genus in Phyllocoptinae or

Cecidophyinae from Acacia burkei

Phyllocoptes sp. (Phyllocoptinae) or new genus

(Cecidophyinae) from Dovyalis zeyheri probably a new genus (subfamily uncertain) from Cussonia sp.

DIPTILOMIOPIDAE

Diptilomiopinae

absent

?

present

?

present separated separated separated

?

separated?

separated?

separated?

3.78

3.79

3.80

3.81

3.82

3.83

3.84

3.85

Diptilomiopus apobrevis sp. nov. from Apodytes dimidiata

Diptilomiopus faurius sp. nov.

from Faurea rochetiana unidentified species (Diptilomiopinae) from Xymalos monospora probably a new genus nr. Dacundiopus from Mystroxylon aethiopicum

Rhynacus sp. cf. Rhynacus sp. nov. from Dovyalis zeyheri

ERIOPHYOIDEA (family uncertain)

probably a new genus (Eriophyidae) from Searsia lancea blisters unidentified morphospecies 2 (cf. Eriophyidae) from Anthocleista grandiflora unidentified species (Eriophyoidea) from Sideroxylon inerme absent absent absent absent absent?

absent

? (may be covered by palpi) absent separated?

touching separated?

Char 4

ep

Char 5 orientation ep direction

? erect

? erect

9.5 appressed

? erect

? erect

? erect

8.9 erect slightly separated; elevated separated; elevated separated; elevated separated; elevated separated; elevated

18.4 (lateral) erect

23.7 (lateral) erect

10.7 (lateral) erect

20.0 (lateral) erect

20.0 erect

? absent?

8.5 (lateral) erect

5.5 (lateral) erect converging converging converging converging?

medially

?

absent?

medially

Char 6

ep

position

?

converging4.6 (lateral)

4.5

?

?

5.0

diverging 21.6 (lateral) diverging 18.0 (lateral)

18.8

?

5.5 (lateral) converging2.2 (lateral)

Char 7 Char 8

ep

rposition ridges or depressions

? no ridges

? single vertical lobe like ridge antaxially of seta ep

2.1

two slight parallel ridges one extending from seta ep , and the other antaxially of seta ep , forming a slight trough

? ?

?

single ridge roundish diagonally from the outside of seta ep towards lateral outside of palpcoxal base unornamented

? possibly with a diagonal rounded slight ridge from ep to the outside

1.8 no ridges?

unornamented unornamented?

1.2 slight depressions ahead of and laterally on palpcoxal base

1.1 short ridges alongside ep , depression ahead of ep

1.1 ep in slight depression half round "platform" proximally and pointed "knob" towards the

1.1

outside of palpcoxal base

1.1 longitudinal ridge on lateral aspect of palpcoxal base?

? ?

1.5 longitudinal ridge on the outside of seta ep three longitudinal ridges: one extending from ep , and two ridges

2.5

antaxially of ep

Char 9 ornamentation (other than ridges)

unornamented unornamented unornamented

?

unornamented unornamented unornamented unornamented unornamented

?

unornamented unornamented

Table 3.4. New potentially useful gnathosomal characters for systematics. Character states were scored from SEM images (Figs 3.25-3.85). char = character; cs = protuberances (possibly papillae, setae or spines) proximally on the chelicerae; approximation = dorsal approximation of pedipalp coxal base segment edges; ep orientation = orientation of seta ep in relation to the palp surface; ep direction = anteriad direction of seta ep ; ep position = distance of seta ep from palpcoxal base segment distal margin; ep r-position = relative position of seta ep on basal segment (basal segment length / distance of seta ep from distal margin); stylet elevation = elevation of chelicerae and other stylets above palpi at about level of proximal margin; ? = unknown (could not be determined, or scored state uncertain).

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment

Char 4 Char 5 Char 6 Char 7 Char 8 Char 9

Fig.

3.25

Mite species and classification

PHYTOPTIDAE

Nalepellinae: Trisetacini

Trisetacus sp. cf . T. pinastri from Pinus pinaster

Nalepellinae: Nalepellini cs

? (may be covered by palpi)

approximation

& shape

touching; curved

length

ep

orientation ep direction

10.6 appressed parallel

ep

position

5.5

ep

rposition ridges or depressions

1.9 no ridges

ornamentation (other than ridges)

unornamented

?

touching; straight

20.0 erect?

parallel 18.8

1.1

longitudinal ridge along the extended inside margin of ep terminating in an ovalish depression, margined with a slight ridge, distally (Fig. 2a) unornamented

3.26

3.27

Setoptus radiatae

from Pinus radiata

Sierraphytoptinae: Mackiellini

Mackiella sp. from Phoenix reclinata

ERIOPHYIDAE

Aberoptinae

?

?

? ?

?

?

?

?

ridge on the outer side of the enlarged cheliceral bases and insertion of

ep , causing these structures to be enclosed in a hollow with ep inserted

1.9

on vertical edges (Fig. 4a) unornamented

3.28

Aberoptus sp. cf . Aberoptus sp. nov.

from Schotia brachypetala

Cecidophyinae: Cecidophyini

absent separated; straight, parallel

7.5 erect medially 4.0

3.29

3.30

3.31

3.32

3.33

3.34

3.37

3.38

3.39

3.40

3.41

3.42

3.43

3.44

Cecidophyopsis sp. cf. C. hendersoni from Yucca guatemalensis

Cecidophyinae: Colomerini

Afromerus lindquisti

from Psydrax livida

Ectomerus sp. cf . E. systenus from Terminalia sericea

Neserella sp. cf. N. tremae from Trema orientalis

Eriophyinae: Aceriini

Acalitus mallyi

from Vangueria infausta subsp. infausta

Aceria lantanae (flower gall race) from Lantana x camara (hybrid complex)

Aceria ocellatum

from Searsia lancea present in immature, could not be determined in adult absent

?

absent absent present touching; straight separated; curved separated; slightly curved separated; curved separated; slightly curved separated; curved

11.2 erect

5.0 erect

4.0 erect

2.7 erect

6.8 appressed

7.0 erect medially medially converging converging parallel parallel

8.1

2.8

2.2

1.3

3.0

3.2

3.35

3.36

3.45

absent separated; curved 4.8 appressed converging 2.5

Aceria sp. cf. A. dichrostachyia from Dichrostachys cinerea subsp. and var. unknown absent or very slight

Aceria sp. cf. A. giraffae from Acacia erioloba

Aceria sp. cf . Aceria sp. nov.

present absent separated; slightly curved separated?

separated from Chrysanthemoides incana

Aceria cf. Aceria sp. nov. from C. monilifera subsp. monilifera

Aceria sp. cf. A. proteae absent separated separated; absent or very slight straight?

from Protea caffra subsp. caffra

Aceria sp. cf. Aceria sp. nov. from Ipomoea batatas var. batatas

Aceria sp. cf . Aceria sp. nov. present separated present separated from Oxalis corniculata

Aceria sp. cf. Aceria sp. nov. from Acacia rehmanniana

Unknown genus, nr. Aceria from Apodytes dimidiata subsp. dimidiata

cf. Aceria sp. from Cineraria sp.

present?

present absent?

separated separated; straight?

separated

4.6 erect

7.0 appressed

6.5 erect

6.7 erect

8.0 appressed

6.0 erect

7.0 erect

6.4 erect

6.4 appressed

? (too slanted) erect parallel converging parallel?

parallel?

converging parallel parallel parallel converging

2.3

3.6

2.8

2.8

4.8

3.6

3.6

3.0

3.4

parallel ? (too slanted)

1.4

ridge extending in a half circle from seta ep to the proximal margin on the outer side of the palpcoxal base; setae ep inserted in relatively vertical palp edges, causing the setae to project medially

1.8 no ridges

1.8 no ridges

2.0 no ridges

2.3 no ridges

2.2 no ridges

1.9 no ridges

2.0

strong ridge running to outside from seta ep , forking; strong diagonal ridge from below ep to distal coxal base margin (Fig. 12a)

2.0 slight ridge running from seta ep diagonally to outside

1.7 possibly very slight ridge running to outside from seta ep

1.7 possibly very slight ridge running to outside from seta ep

2.0 no ridges

2.1 no ridges

1.9 no ridges

? possibly very slight ridge running to outside from seta ep unornamented unornamented unornamented unornamented unornamented unornamented unornamented unornamented unornamented

2.3 two slight parallel ridges antaxially of seta ep , forming a slight trough unornamented two tubercles close to proximal

2.4 two slight parallel ridges antaxially of seta ep , forming a slight trough margin?

unornamented unornamented unornamented unornamented unornamented unornamented

?

Fig.

Mite species and classification

3.46

3.47

3.48

3.49

3.50

3.51

3.52

3.53

3.54

3.55

3.56

3.57

3.58

Aceria sp. cf. Aceria sp. nov. from Xymalos monospora

Phyllocoptinae: Acaricalini

Tumescoptes sp. cf. T. dicrus from Phoenix reclinata

Phyllocoptinae: Calacarini

Calacarus sp. from Searsia lancea

Calacarus sp. from Faurea rochetiana

Calacarus sp. from Psydrax livida

Phyllocoptinae: Tegonotini

Shevtchenkella sp. cf. S. lividae from Psydrax livida

Shevtchenkella sp. cf . S. rhusi from Rhus lancea

?

present?

?

?

absent?

absent?

?

Neoshevtchenkella or Shevtchenkella sp. (with wax) from Celtis africana

Phyllocoptinae: Phyllocoptini

cf. Calepitrimerus sp.

from Celtis africana

Cecidodectes euzonus

from Trema orientalis

cf. Phyllocoptes sp. from Anthocleista grandiflora

Tergilatus sparsus

from Portulacaria afra

Phyllocoptinae: Anthocoptini

Aculops or Metaculus sp. from Anthocleista grandiflora absent?

present absent present present absent?

3.59

3.60

3.61

Aculus sp. cf . Aculops lycopersici from Physalis peruviana

cf. Aculus sp. from Acacia burkei

cf. Aculus sp. from Lantana trifolia

3.62

3.63

3.64

3.65

3.66

3.67

3.68

3.69

3.70

cf. Aculus sp. or possibly immature of Quantalitus from Rothmannia capensis

Costarectus zeyheri

from Dovyalis zeyheri

Meyerella bicristatus

from Mystroxylon aethiopicum possibly a new genus nr. Costarectus from Mystroxylon aethiopicum possibly a new genus nr. Tetra from Protea caffra subsp. caffra possibly a new genus nr. Mesalox from Apodytes dimidiata

Porosus monosporae

from Xymalos monospora

Tegolophus sp. cf. T. orientalis from Trema orientalis

Tetra retusa

from Bauhinia galpinii present present present

?

?

present present

?

present

?

?

present

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment cs approximation

& shape length

separated separated separated?

separated?

separated

Char 4

5.5 (lateral) erect

? erect

? erect

? erect

? erect

Char 5

ep

orientation ep direction

Char 6

ep

position

Char 7 Char 8

ep

rposition ridges or depressions

Char 9 ornamentation (other than ridges)

tubercles or granula particularly in area distally of insertion of seta ep from anterior to lateral region (Fig.

22b) converging2.8 (lateral)2 (lateral) no ridges converging?

?

?

9.4 (lateral) parallel? 11.0 (lateral) converging8.9 (lateral)

? possibly no ridges possibly unornamented

?

ridge extending in a half circle from seta ep to the proximal margin on the outer side of the palpcoxal base ridge extending in a half circle from seta ep to the proximal margin on

?

the outer side of the palpcoxal base ridge extending in a half circle from seta ep to the proximal margin on

?

the outer side of the palpcoxal base unornamented unornamented unornamented separated separated?

separated?

separated?

separated separated separated separated separated separated?

separated separated?

separated?

separated separated?

separated?

separated

?

separated?

separated

? erect

? erect

? erect

? erect

7 (lateral) erect

? erect

? erect

? erect

7.9 erect

? erect

6.3 erect

? erect

? erect

6.0 erect

? erect

? ?

9.4 (lateral) erect

? ?

? erect

5.5 erect converging4.1 (lateral) parallel converging converging4.3 (lateral) parallel?

3.4 (lateral) converging converging?

converging parallel?

converging

?

?

?

? no ridges?

? no ridges?

? no ridges?

unornamented?

unornamented?

unornamented?

? no ridges?

unornamented?

2.0 no ridges granulated ridge diagonally downwards from seta ep (similar to this

?

ridge in other species) (Fig. 33a) transverse ridge proximally on palpcoxal base in immature, presence

?

not determined in adult unornamented granulated (Fig. 33a) unornamented

4.5

3.7

?

3.3

? no ridges?

ridge extending in a half circle from seta ep to the proximal margin on

2.1

the outer side of the palpcoxal base, more vague and larger circle than those in Calacarus spp.

unornamented?

unornamented

? half circular ridge running diagonally on outside of ep unornamented

1.9 slight ridge running from seta ep diagonally to outside few slight granules converging?

converging

?

?

converging6.1 (lateral)

?

?

converging converging

?

3.0

?

4.0

? single lobe like ridge on the outside of seta ep

? single vertical lobe like ridge antaxially of seta ep unornamented unornamented

1.5 no ridges unornamented

? no ridges

?

probably a lobe like vertical ridge on the outside edge of a diagonal ridge running from ep backwards

1.5

no ridges or possibly very slight ovalish area diagonally on coxal base demarcated by very slight ridges, barely visibly unornamented unornamented unornamented

? ?

? no ridges?

1.8 single diagonal ridge from ep to distal margin of palp coxal base

?

unornamented?

unornamented

Char 1 Char 2 Char 3 dorsal aspect of palpcoxal base segment cs approximation

& shape length

Fig.

Mite species and classification

3.71

3.72

3.73

3.74

3.75

3.76

3.77

Tetraspinus sp. from Chrysanthemoides monilifera subsp. monilifera present

cf. Tetraspinus sp. from Faurea rochetiana present

Eriophyidae (subfamily uncertain)

possibly new worm-like genus (Eriophyinae?:

Aceriini?) from Faurea rochetiana unknown genus (Phyllocoptinae?) from Ekebergia capensis possibly a new genus in Phyllocoptinae or

Cecidophyinae from Acacia burkei

Phyllocoptes sp. (Phyllocoptinae) or new genus

(Cecidophyinae) from Dovyalis zeyheri probably a new genus (subfamily uncertain) from Cussonia sp.

DIPTILOMIOPIDAE

Diptilomiopinae

absent

?

present

?

present separated separated separated

?

separated?

separated?

separated?

3.78

3.79

3.80

3.81

3.82

3.83

3.84

3.85

Diptilomiopus apobrevis sp. nov. from Apodytes dimidiata

Diptilomiopus faurius sp. nov.

from Faurea rochetiana unidentified species (Diptilomiopinae) from Xymalos monospora probably a new genus nr. Dacundiopus from Mystroxylon aethiopicum

Rhynacus sp. cf. Rhynacus sp. nov. from Dovyalis zeyheri

ERIOPHYOIDEA (family uncertain)

probably a new genus (Eriophyidae) from Searsia lancea blisters unidentified morphospecies 2 (cf. Eriophyidae) from Anthocleista grandiflora unidentified species (Eriophyoidea) from Sideroxylon inerme absent absent absent absent absent?

absent

? (may be covered by palpi) absent separated?

touching separated?

Char 4

ep

Char 5 orientation ep direction

? erect

? erect

9.5 appressed

? erect

? erect

? erect

8.9 erect slightly separated; elevated separated; elevated separated; elevated separated; elevated separated; elevated

18.4 (lateral) erect

23.7 (lateral) erect

10.7 (lateral) erect

20.0 (lateral) erect

20.0 erect

? absent?

8.5 (lateral) erect

5.5 (lateral) erect converging converging converging converging?

medially

?

absent?

medially

Char 6

ep

position

?

converging4.6 (lateral)

4.5

?

?

5.0

diverging 21.6 (lateral) diverging 18.0 (lateral)

18.8

?

5.5 (lateral) converging2.2 (lateral)

Char 7 Char 8

ep

rposition ridges or depressions

? no ridges

? single vertical lobe like ridge antaxially of seta ep

2.1

two slight parallel ridges one extending from seta ep , and the other antaxially of seta ep , forming a slight trough

? ?

?

single ridge roundish diagonally from the outside of seta ep towards lateral outside of palpcoxal base unornamented

? possibly with a diagonal rounded slight ridge from ep to the outside

1.8 no ridges?

unornamented unornamented?

1.2 slight depressions ahead of and laterally on palpcoxal base

1.1 short ridges alongside ep , depression ahead of ep

1.1 ep in slight depression half round "platform" proximally and pointed "knob" towards the

1.1

outside of palpcoxal base

1.1 longitudinal ridge on lateral aspect of palpcoxal base?

? ?

1.5 longitudinal ridge on the outside of seta ep three longitudinal ridges: one extending from ep , and two ridges

2.5

antaxially of ep

Char 9 ornamentation (other than ridges)

unornamented unornamented unornamented

?

unornamented unornamented unornamented unornamented unornamented

?

unornamented unornamented

I could not study the division of the cheliceral shaft, because the gnathosoma was studied intact and in a natural condition, and the shafts of the chelicerae were largely not visible. The cheliceral shafts are directly linked and hinged to the medial motivator (De Lillo et al., 2001). The bases of the cheliceral shafts are bulbous, thicker and more robust and may be articulated to the distal needle-like dorsal and ventral cheliceral digits (Shevchenko & Silvere, 1968; Thomsen, 1987).

Only the bulbous cheliceral shaft bases, with medially possibly part of the dorsal aspect of the motivator, and the proximal part of the more slender distal digit of the dorsal cheliceral shaft or modified fixed digit, are usually exposed (e.g., Figs 3.33a, b). The remaining parts of the chelicerae and other stylets in the Phytoptidae and Eriophyidae are covered by the overlapping stylet sheath (e.g., Figs 3.33a, b), which was also recorded by, e.g., Nuzzaci & Alberti (1996). In the SEM images by Thomsen (1987) and Nuzzaci & Alberti (1996: 107 – Fig. 1.2.4) this sheath can also be seen enclosed around the distal end of the stylets, forming the tip of the subcapitulum.

The shape of the chelicerae, stylet sheath and palpi are different in the Diptilomiopidae. The chelicerae, partly covered by the sheath, are elevated above the palpi (Fig. 3.79b), and the stylet sheath overlaps the cheliceral shafts more distally (Fig. 3.79a).

Two additional cheliceral characters are recorded in the present study:

a. Character 1 (Table 3.4). Protuberances on cheliceral shafts

Cheliceral setae occur in other mite groups, but are absent in the Eriophyoidea (Lindquist,

1996a). The internal sensillar structures of eriophyoid chelicerae were described by De Lillo

et al

. (2001). The external morphology of these structures, however, and whether there are obvious external protuberances associated with them, their shape and location on the chelicerae were not reported. In the present study a protuberance that could be a papilla, spine, or seta, was detected on the proximal and dorsally exposed aspect of each dorsal cheliceral shaft of some species, mostly closely above the upper margin of the overlapping stylet sheaths

(e.g., Figs 3.29b, d; 3.54c, d; 3.57a-d). This character could not be scored in many species, and no comprehensive attempt was made to determine particular patterns in the occurrence and size of these protuberances. They, however, broadly seem to be more frequently present and more pronounced in species of the Phyllocoptinae (e.g., Aculus sp., Figs 3.60a, b, d), and are smaller or absent in species from other subfamilies included in present study (e.g., Acalitus

mallyi

, Figs 3.33a, b). In most species the protuberances do not seem to be symmetrical, with the protuberance of one chelicera being larger than the other (e.g., Phyllocoptes sp., Figs

3.56a, b, d). In the latter species, it further seems as if the structures might be setae, because they seem to be inserted on tubercles (Figs 3.56a, b, d), but this is inconclusive, and as with the uncertain presence of additional setae on the palpi (Fig. 3.42) discussed later on, further

Chapter 3. Morphology.

103

investigation, especially whether the structures are birefringent in polarized light, is needed to clarify the matter.

b. Inter-locking mechanism (Fig. 3.25) at the cheliceral bases

In Trisetacus sp. (Fig. 3.25) in the present SEM study, structures of the cheliceral bases seem to inter-lock with the palpcoxal base segments (Figs 3.25a, b, c, d). This mechanism may be in place of the cheliceral retainer mechanism which is usually present. The cheliceral retainers are structures of the palpi which inter-lock with parts of the cheliceral bases. These mechanisms probably keep the stylets and palpi in place when the mite is not feeding.

Unfortunately, this basal gnathosomal area is obscured by the frontal lobe in the other two phytoptine species studied (Figs 3.26 & 3.27), and no similar cheliceral base inter-locking structures are present in any of the other species in which this area was visible. This character is thus unique (autapomorphic) to Trisetacus sp. and has not been scored as a character in

Table 3.4.

3.5.2

Palpi (pedipalpi)

The palpi of the Actinotrichida [of which the Acariformes (including the Prostigmata, and the

Eriophyoidea) is a subgroup] show considerable variation in their segmentation and shape (Evans,

1992; Kethley, 1990). Primitively within the Prostigmata, the palp is a leg-like, tactile structure comprising five homogenous articulating free segments (trochanter, femur, genu, tibia and tarsus)

(Kethley, 1990). The palpcoxa is never a free segment in the Acariformes (Lindquist, 1996a).

Eriophyoid palpi are well-developed stout structures with truncated flattened surfaces apically, and they flank and support the subcapitulum. They may be reduced in segmentation due to fusion of some of the segments, depending on the interpretation of the palp structures. It is important to identify the palp segments and homologize them and their structures with those of other acariform mites in order to study the relationships between eriophyoids and other acariform mites. Keifer

(1959a) noted that: “These (eriophyoid) palpi have a series of segments, and while this recital will

not attempt to definitely designate what each of these segments is, there is a possibility that all six segments of the Acarine palp are actually present

”. He designated the “oral plate” in front of coxisternal plates I to be the basal or first palp segment (Figs 3.23c, d), and denoted the palp base

(sensu Lindquist, 1996a) as the second palp segment and called it the “proximal segment”.

Nuzzaci (1979) stated that the palpi are articulated post-oral appendages [four free segments according to Keifer (1975a) (Fig. 3.23d), and five segments according to Shevchenko & Silvere

Chapter 3. Morphology.

104

(1968) (Fig. 3.23c)]. Lindquist (1996a) hypothesized that each palp appears to consist of a base and three free segments (Figs 3.23a, b).

The palpcoxal base (called the “proximal segment” or “basal palp segment” by Keifer, 1959a,

1975a) is situated at the proximal end of the palpi. It is presumed that, similar to the gnathosoma of other Acari, the enlarged coxae of the palpi of the Eriophyoidea form the external walls of the subcapitulum by meeting and fusing ventrally (Evans, 1992), and thus the palpcoxa is not a free segment. The basal segment appears to be a projection of the dorsal portion of the palpcoxal base

(Lindquist, 1996a).

• Palpcoxal base (“basal palp segment”)

The present study confirms Lindquist’s (1996a) observation that the basal segment is a projection of the dorsal portion of the palpcoxal base, because it is clear the segment extends uninterruptedly dorso-ventrally (Figs 3.41g, h). Ventrally, it extends to form the subcapitulum that consists of the basal part of the stylet sheath and the “oral plate” of Keifer (Figs 3.20 & 3.41g, h). It could be possible that leg coxisternal elements contribute to the “oral plate” structure. o

Shape of the palpcoxal base segment (dorsally)

Characteristics of the shape of the dorsal aspect of the palpcoxal base have not previously been used in the systematics of the Eriophyoidea. Some discrete differences may be of use particularly in studying the phylogeny. This segment is usually deformed in the slide-mounting process so the shape characteristics cannot be determined in slide-mounted specimens.

Characters from the shape of the palpcoxal base that are recorded in the present study:

a.

Character 2 (Table 3.4). Approximation of inner margins of the palpcoxal

segments dorsally

Dorsally, the inner margins of the palpcoxal bases differ, as well as their relationship or approximation towards each other. The approximation of the margins (either touching or separate) could be scored most of the time, but the shape of the inner margins was not clear in most species.

However, there are shape differences in the margin, such as rounded in Trisetacus sp. and

Afromerus

sp. (Figs 3.25 & 3.30, respectively), and straight or parallel in Setoptus radiatae and

Aberoptus

sp. (Figs 3.26 & 3.28, respectively). In the Diptilomiopinae, this segment is partly elevated against the stylets, and is separated by the stylets. The character states are presented in

Table 3.4 (Character 2), and are given as approximations, followed by the shape of the margins.

These two character states can be scored separately if they turn out to be informative.

Chapter 3. Morphology.

105

b.

Character 3 (Table 3.4). Length of the palpcoxal base segment

The length was measured on the SEM images on the straight-most and shortest distance from the base of the segment where it borders the frontal margin of the prodorsal shield areas, not including the anterior shield lobe, up to the furthest distance on the anterior margin, preferably in line with the base of ep if possible (dashed black lines in Figs 3.25c, 3.28c, 3.38b, 3.55a, 3.79b). It was preferably measured on the dorsal view image, but if this is not optimal, it was measured on the lateral view image (e.g., dashed black lines in Figs 3.55a, 3.79b) and has been indicated as such in

Table 3.4. The length of the scale bar was used to calculate the real length in µm. o

Structures on the dorsal surface of the palpcoxal base

Two structures on the dorsal surface of the palpcoxal base are sometimes included in eriophyoid taxonomy:

c.

Cheliceral retainer

A seemingly flexible, spine-like process which is slightly darker than the surrounding dorsal palpcoxal surface is visible, one on each palpcoxal base, in slide-mounted specimens, and in some species it is easily discernable. It is directed almost centrally. It was named the “cheliceral retainer” by Keifer (1959a, 1975a). Similar to other structures on the gnathosoma, the cheliceral retainer is pushed out of place, usually out-wards, by the slide-mounting process: for example see drawings of Cecidophyopsis spp. (Fig. 3.24) from Amrine et al. (1994). This is also the case in most published SEM images of the gnathosoma and in the present study they are out of place in

Cecidophyopsis

sp. specimen (Fig. 3.29j). Sometimes the retainer itself flips towards the outside

(Fig. 3.24d).

The shape of the cheliceral retainer was not scored, because it is not visible in most of the images of specimens in the current study, because the gnathosomas were not distorted, and are in their natural “non-feeding” state. The retainer is inter-locked with, or partly hooked around the enlarged knob-like base of the chelicera (e.g., Fig. 3.41b). It is obscured by the anterior shield lobe and anterior structures of the prodorsum. Part of the base of the cheliceral retainer is probably covered by the enlarged cheliceral base when they are “inter-locked”, and therefore, it may appear narrower in the SEM image. The “true” shape of the cheliceral retainer is thus probably as exposed in slide-mounted specimens, or when the mouth-parts are “pulled apart” and the cheliceral retainer exposed in SEM images, such as that of Cecidophyopsis grossulariae (Fig.

10c, p. 160 in Amrine et al., 1994) and Cecidophyopsis sp. specimen (Fig. 3.29j). In the case of the cheliceral retainer, it might not be the best option to study the shape on intact SEM images as

Chapter 3. Morphology.

106

found in the current study, but rather in either slide-mounted specimens or in SEM images where the cheliceral retainer is exposed.

Amrine et al. (1994) included the shape of the cheliceral retainer of the species in his description of Cecidophyopsis spp. from Ribes spp.: C. ribis and C. selachodon (Fig. 3.24a) with cheliceral retainers similar, fairly large, triangular, directed mesally or upward; C. grossulariae with cheliceral retainers depicted in drawing (Fig. 3.24b), but not described in text; C. aurea (Fig.

3.24c) with cheliceral retainer nearer to ep than the other species, narrowly triangular; C. alpina

(Fig. 3.24d), with the cheliceral retainer fairly large, triangular and directed mesally or upward.

The shape and position as described in the text by Amrine et al. (1994) do not correspond with the selective depiction of it for the species, showing that it is not easy to score this character, but even if it corresponded, the differences are not particularly marked.

a b c d

cr cr cr cr

C. selachodon C. grossulariae C. aurea C. alpina

“as in C. ribis: fairly large, triangular, directed mesally or upward” not described in text “nearer to basal setae than other species, narrowly triangular”

“fairly large, triangular and directed mesally or upward”

Fig. 3.24. Dorsal view of gnathosomas of: a) Cecidophyopsis selachodon; b) C. grossulariae; c) C. aurea and d) C.

alpina

. cr = cheliceral retainer. Below drawings with species names are the descriptions of the cheliceral retainers from

Amrine et al. (1994). Cheliceral retainers of C. ribis are not depicted in Amrine et al. (1994). The cheliceral retainer on the right in C. selachodon and on the left in C. alpina flipped over, caused by the slide-mounting process. Drawings were scanned from Amrine et al. (1994) (with permission from the author), and were cropped and enlarged or made smaller so that scale lines (10 µm) are all the same length, and thus drawings are at about the same scale.

The shape of the cheliceral retainer in the SEM images of the current study is clearly different between species. It should be taken into account that the differences are between species of different genera, and not between morphologically very similar species such as the Cecidophyopsis spp. (Amrine et al., 1994). For example, compare the cheliceral retainer in the adults of Acalitus

mallyi

(Fig. 3.33), Aceria sp. from Ipomoea batatas (Fig. 3.41) (more structured) and Aceria

lantanae

(Fig. 3.34) (shallower and more rounded than in Acalitus mallyi and Aceria sp. from

Ipomoea batatas

) and immatures of Neserella tremae (Fig. 3.32), and Tergilatus sparsus (Fig.

3.57). This character has potential as a systematic character, but it needs to be determined how the

Chapter 3. Morphology.

107

specimens should be preserved and studied from which it must be scored. The enlarged cheliceral base around which the cheliceral retainer is “locked” also differs in size and shape, and may be of systematic use, but it was not scored in the present study. For example, it is quite rounded in

Aberoptus

sp. from Schotia brachypetala (Figs 3.28a, c), and more oval-shaped and less bulbous in Aceria ocellatum (Fig. 3.35a).

d.

Seta ep

The second structure of possible taxonomic importance is a seta, one present on each palpcoxal base, named “basal seta” by Keifer (1959a; 1975a). Lindquist (1996a) hypothesized that this seta appears to represent the palpcoxal seta, ep, based on its dorsoproximal position. He regarded it to be surprisingly well-developed in the Eriophyoidea, compared with its usually reduced size in other trombidiform or prostigmatid mites, when present. He thought that this may be due to its exposed position, in contrast with being covered by the basis of chelicera in the other groups.

In other prostigmatid groups the seta homologous to ep in the Eriophyoidea (according to

Lindquist, 1996a) is named supracoxal seta (e) and is normally present and situated above the palp base, one on each side of the subcapitulum, and occurs additionally to the infracapitular seta of the gnathosoma that is usually present (Evans, 1992). The “pair of palp supracoxal setae”, e, occurs dorsally at the bases of the palpi in the Tetranychoidea, but is often difficult to discern in the

Tetranychidae (Lindquist, 1985). Seta e in the Tetranychidae is spine-like in comparison to the

“normal” ep in the Eriophyoidea (E.A. Ueckermann, pers. comm., 2008).

Currently, the presence of ep is sometimes recorded and/or depicted in eriophyoid descriptions.

The length of ep is not always given, but should be included based on advice of Amrine & Manson

(1996). J.W. Amrine Jr. (pers. comm., 2008) suggested that the position of ep may be of taxonomic value. Seta ep is always present in eriophyoid species so far known.

In the present explorative study, the characteristics already used in taxonomy, namely presence and length of ep, were not recorded. Three new characteristics of ep that may be of use to systematics were observed and scored as an attempt to identify new characters of potential systematic value. These are:

i.

Character 4 (Table 3.4). Orientation of ep in relation to palp surface, either flat

on the surface or projecting away (up) from it:

e.g., they are lying flat in Trisetacus sp. from Pinus pinaster (Fig. 3.25e) and Aceria

ocellatum

(Figs 3.35a, c), In general, they seem to be lying flat in some Aceria and

Chapter 3. Morphology.

108

other species of the Aceriini, and in Trisetacus (Trisetacini) and projecting up in all others (e.g., in cf. Aculus sp. from Lantana trifolia Figs 3.61b, c, h). When lying flat, they are either projecting parallel or convergent anteriorly.

ii.

Character 5 (Table 3.4). Anteriad direction of ep: e.g., they are projecting parallel anteriad in Trisetacus sp. from Pinus pinaster (Figs

3.25a, c), anteriad converging in Aceria ocellatum (Fig. 3.35a), and anteriad medially in Aberoptus sp. from Schotia brachypetala (Figs 3.28a, c).

iii.

Character 6 (Table 3.4). Position of ep from distal margin of palpcoxal base

segment (gray line in Fig. 3.25c).

iv.

Character 7 (Table 3.4). Relative position of ep:

Relative position of ep was calculated by dividing the palpcoxal base segment length (Character 3) by the position of ep on the palpcoxal base segment (character

6). o

Possible additional setae on the palpcoxal base

A structure, first thought to be a second seta, was found antaxially of ep on the palpcoxal base

(Figs 3.42a, b, d, e, g) of a new Aceria sp. collected on Oxalis corniculata. The shape of this structure did not seem to be similar to that of spines or other known protuberances observed in the

SEM images in the present study. Although the structure seems like a small version of ep, thus probably being a seta, it is difficult to verify this in slide-mounted specimens studied with phase contrast light microscopy. E.E. Lindquist (pers. comm., 20 September 2007) commented that it is generally accepted that the seta occurring dorsally on the palpcoxa of many superfamilies of the acariform mites is the palp supracoxal seta (ep in the case of the Eriophyoidea), and that no other seta is known to occur in this area, and that it is thus not likely that it is, in fact, a seta. The structure is very small and stretches the limits of resolution in phase contrast light microscopy.

Using 1600 x magnification on slide-mounted specimens, it appears rather more spine-like than seta-like, but it is not conclusive. Further investigation, especially whether the structure is birefringent with polarized light, is needed to clarify this matter. A probably homologous structure in the same position has been described in Acaphyllisa limitata (Flechtmann & Etienne, 2001)

(Fig. 3.42f reproduced from Flechtmann & Etienne, 2001). Flechtmann & Etienne (2001) regarded it to be a seta, but did not comment on the occurrence of this seta in the Eriophyoidea, or speculated on the possible homology of this seta with setae in other acariform mites. It is not common in the Eriophyoidea that ep is inserted on a tubercle, and ep and the new seta are depicted by them to be inserted on tubercles. Material of the latter species should be re-examined to verify the matter. In the new Aceria sp. from Oxalis corniculata in the present study, a third extremely

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109

small protuberance is present on the adaxial side of the second protuberance, if ep is regarded as the first seta (Figs 3.42a, b, e). It was clearly present in all SEM images taken of this aspect of the palpi in this species. o

Ornamentation of the palpcoxal base segment

Ornamentation is present on the dorsal surface of the palpcoxal segment of some species. In so far as could be established, similar ornamentation of palp segments has not been used in taxonomy of the Eriophyoidea, and may be of use, particularly for phylogenetic studies. It is doubtful whether these ornamentations will be clearly visible in slide-mounted specimens.

i.

Character 8 (Table 3.4). Presence of ridges or depressions on palpcoxal base

segment:

e.g., a longitudinal ridge is present along the extended inside margin of ep, terminating in a distal ovalish depression margined with a slight ridge in Setoptus

radiatae

from Pinus radiata.

ii.

Character 9 (Table 3.4). Ornamentation, other than ridges, on the palpcoxal

base segment:

e.g., tubercles or granula are present from the dorsal to the lateral region, particularly in the area distally of the insertion of ep in Aceria sp. nov. from

Xymalos monospora

(Fig. 22b).

First or proximal articulating palp segment (dorsally)

The next palp segment, apical to the palpcoxal base, considered by Lindquist (1996a) to be the first articulating palp segment, is formed by the fusion of the trochanter, femur and genu.

Presently only the presence, shape and length of d on this segment are sometimes used in taxonomy. The scoring of Characters 17 – 20 (Table 3.4) is from this segment.

i.

Character 17 (Table 3.4). Position of d:

Although the position differed slightly between species [e.g., it seems to be on the genu, close to the proximal genu margin in Setoptus radiatae (Fig. 3.26d) and possibly closer to the distal genu margin in Aceria sp. from Acacia erioloba (Fig.

3.37d)], it turned out to be less variable than was perceived before scoring. It is still included, however, because the character may turn out to be useful for systematics in future.

ii.

Character 18 (Table 3.4). Ornamentation or structures present dorsally:

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110

The trochanter-femur-genu was usually unornamented, except some structures which are autapomorphic for a single species. This character may become more informative when more species are studied in future.

iii.

Character 19 (Table 3.4). General shape:

This character needs further study for evaluating its possible systematic value.

iv.

Character 20 (Table 3.4). Elevation of chelicerae above the palpi:

The chelicerae are sometimes elevated above the palpi at the level of the proximal margin of the trochanter-femur-genu segment, and the presence of and extent of elevation were scored (Character 19). They are particularly elevated above the palpi in the diptilomiopid species, such as Diptilomiopus faurius sp. nov. (Fig.

3.79b). It is slightly elevated in many other species, such as the possibly new genus from Apodytes dimidiata (Fig. 3.67b), but not elevated in, for example, Neserella sp. from Trema orientalis (Figs 3.32a, c).

• The ventral aspect of the gnathosoma

The ventral surface of the gnathosoma is reduced because of the hypognathous position of the gnathosoma in most eriophyoid species. Several characters were scored from this aspect

(Characters 10–16, 21, Table 3.4).

i.

Characters 10–16 (Table 3.4). Morphology of the gnathosomal ventral aspect:

The structures and externally identifiable separate areas in these parts of the gnathosoma have hardly been studied, and separate areas were identified for the first time (Figs 3.20, 3.21) in the present study. The identification of homologies between the areas of different species was attempted (Fig. 3.21). The hypothetically homologous areas were indicated in similar colours in Figs 3.20 & 3.21. Several characters were tentatively scored, and mostly involve the shape and position of structures and margins, and ornamentation present. These can be viewed in the

SEM figures of the particular species for each character state (Table 3.4). No attempt was made in present study to evaluate these characters, but there are clear differences that may be of systematic value (Fig. 3.21).

ii.

Character 21 (Table 3.4). Seta v:

Seta v is present ventrally, on the palptarsus sensu Lindquist (1996a). It is uncertain whether it is a seta or solenidion in most species, because it is so small that the presence or absence of birefringence in polarized light cannot be determined. In some diptilomiopid species, however, this seta is quite long (e.g., in the diptilomiopid species included in the present study, Figs 3.78 – 3.82), and was

Chapter 3. Morphology.

111

determined to be a seta in some diptilomiopid species (Lindquist, 1996a). Seta v is inserted right on the distal edge of the tarsus, and frequently lays closely against an indentation of the palp apical lip (e.g., Figs 3.27d, 3.29h, 3.30b). In some species it is inserted on a slight bulge or lobe of the distal part of the tarsus, allowing the seta to be positioned more distally (e.g., in Cecidophyopsis sp. from Yucca

guatemalensis

, Fig. 3.29h; in Afromerus lindquisti, Fig. 3.30b; and in cf. Aculus sp. from Lantana trifolia, Fig. 3.61 e), probably to facilitate it to touch the surface when the palpi are pressed down for feeding. This seta is sometimes hardly visible in slide-mounted specimens of some species, and is usually not described. Studying the SEM images, it was found that it differs in shape and length in different species, and since these characteristics have potential for systematic use, they were scored

(Character 21, Table 3.4).

• Artefacts in SEM images

Smooth, rounded drop-like bumps are frequently present on the surface of the gnathosoma. These may be some liquid that froze, or some growth occurring randomly on some species [e.g., the relatively short, white arrows in Figs 3.25 (Trisetacus sp. from Pinus pinaster), 3.31 (Ectomerus

systenus

), 3.33a (Acalitus mallyi), 3.34a (Aceria lantanae), 3.41a,b (Aceria sp. from Ipomoea

batatas

), 3.43a (Aceria sp. from Acacia rehmanniana) and 3.57b (Tergilatus sparsus)]. It is, however, easily distinguishable from approximately rounded or oval tubercles [e.g., relatively short, white arrows in Figs 3.27d (Mackiella sp. from Phoenix reclinata), 3.29a (Cecidophyopsis sp. from Yucca guatemalensis), and 3.84f (species from Anthocleista grandiflora)].

Other artefacts on specimens are indicated in some figures, but are generally present on many specimens. These include ice crystals and/or dirt, fine cracks, some charging, and the breaking-off of some setae. These are usually identifiable, and can be separated from morphological features, and can be largely rectified by using better equipment for cryo-SEM (see general discussion further on).

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a b e c seta d elongated appendice of d modified cheliceral base fits into a groove of palpcoxal base approximation and shape of palpcoxal base medial edges: touching; curved probably position of motivator to which the cheliceral bases are attached f seta ep projects parallel anteriad seta ep appressed to palp surface bulbous base of chelicera and palpcoxal base probably form an interlocking mechanism

Fig. 3.25. Gnathosoma of Trisetacus sp. cf. T. pinastri Nuzzaci, 1975 (Phytoptidae: Nalepellinae: Trisetacini) from Pinus

pinaster: a, b) dorsal views (probably adults, genders unknown), white arrows indicate droplet-like structures that are probably not part of the mite, but artefacts; c) line drawing of Fig. 3.25a, dashed black line indicates length of palpcoxal base, grey line indicates distance of seta ep from distal margin of palpcoxal base, measured as the shortest distance from the base of seta to distal margin; d) line drawing of enlargement of “cheliceral lock mechanism” in Fig. 3.25b; e) dorsolateral view (probably adult, gender unknown); f) ventral view (male). Scale lines = 10 µm.

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a b c d approximation and shape of palpcoxal base medial edges: touching; straight ovalish depression enclosed by a slight ridge; the ridge may largely be an internal apodeme visible on the surface longitudinal ridge extends from the inside of seta ep seta ep probably erect and projecting parallel anteriad seta d inserted near, or on, the proximal margin of the palp genu, should the margin extend to the anterior aspect of the palpus feeding puncture stylets extend above palpi more or less at the level of the margin between the palpcoxal base and fused trochanter-femur-genu, similar to the gnathosomas of the Diptilomiopidae in this study, but to a lesser extent

Fig. 3.26. Gnathosoma of Setoptus radiatae Meyer, 1991 (Phytoptidae: Nalepellinae: Nalepellini) from Pinus radiata: a) dorsal view (probably adult, gender unknown); b) ventral view (female); c) line drawing of Fig. 3.26a; d) lateral view

(probably adult, gender unknown). Scale lines = 10 µm.

Chapter 3. Morphology.

114

a c d b setae ep obscured by frontal lobe gnathosoma more prognathous division between the palp tibia and -tarsus is not apparent on the surface – the tibia and tarsus may be fused, or partly fused, or they may be separated internally, and separation may become apparent when the segments telescope for feeding e division between the tarsus and socalled palp apical lip is clearly visible on the surface

Fig. 3.27. Gnathosoma of Mackiella sp. (Phytoptidae: Sierraphytoptinae: Mackiellini) from Phoenix reclinata: a) dorsal view (probably adult, gender unknown); b) line drawing of Fig. 3.27a; c) lateral view (male); d) ventral view (male); e) line drawing of Fig. 3.27d; a, b) scale lines = 1 µm; c, d, e) scale lines = 10 µm.

Chapter 3. Morphology.

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a b c ridge on the palpcoxal base, on the outer side of the enlarged cheliceral base, with ep inserted on its vertical aspect, causing these structures to be enclosed in an ovalish slanting hollow approximation and shape of palpcoxal base medial edges: touching; straight, parallel setae ep erect, and projecting medially cheliceral protuberance absent part of cheliceral base apical of the cheliceral retainer rounded and pertinent base of cheliceral retainer d

Fig. 3.28. Gnathosoma of Aberoptus sp. cf. Aberoptus sp. nov. (Eriophyidae: Aberoptinae) from Schotia brachypetala: a) dorsal view (probably adult, gender unknown); b) lateral view (female); c) line drawing of Fig. 3.28a, dashed black line indicates length of palpcoxal base, grey line indicates distance of seta ep from distal margin of palpcoxal base, measured as the shortest distance from the base of seta to distal margin; d) ventral view (female); a, c) scale lines = 1 µm; b, d) scale lines = 10 µm.

Chapter 3. Morphology.

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a b setae d broken off (only in this specimen), but these setae are present, e.g., see adult female on next page c

adult

frontal lobe approximation and shape of palpcoxal base medial edges: touching; straight d frontal lobe e cheliceral protuberance ridge extending in a half circle from seta ep to the proximal margin on the antaxial side of the palpcoxal base seta ep inserted on relatively vertical paraxial palpcoxal aspect; it is erect, and projects medially

Fig. 3.29. (continued on next page). Gnathosoma of Cecidophyopsis sp. cf. C. hendersoni (Keifer, 1954) (Eriophyidae:

Cecidophyinae: Cecidophyini) from Yucca guatemalensis: a) dorso-lateral view (female); b) dorsal view (possibly immature based on gnathosoma morphology); c) line drawing of Fig. 3.29a, showing broken off setae which is possibly an artefact caused by cryo-praparation; d) enlargement of protuberances basally on the chelicerae; e) dorso-lateral view of gnathosoma of just-born larva still emerging from egg; a, c, e) scale lines = 10

µm; d) scale line = 1 µm.

Chapter 3. Morphology.

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f distal palp segments (tarsus, tibia and genu) telescoped to extrude gnathosomal stylets, and will subsequently press the palp apical lips against a plant surface to aid penetration of stylets before and/or during feeding; partial proximal ventral margin of genu lobe-like, probably partly facilitating telescoping g h i seta d stylet sheath seta ep erect, and projects medially cheliceral retainer j chelicera?

auxilliary stylet?

frontal lobe rounded half-circle ridge on the palpcoxal base antaxial of seta ep palpi slightly pulled apart, “dislocked” from chelicerae, and stylets “lowered” probably in preparation to feed

Fig. 3.29. (continued from previous page). Gnathosoma of Cecidophyopsis sp. cf. C. hendersoni: f) ventral view (female);

g) lateral view, gnathosoma with apical palp segments telescoping for feeding (female); h) lateral view (female); i) line drawing of Fig. 3.29j; j) ventro-lateral view of gnathosoma (female); f, g, h, j) scale lines = 10 µm; i) scale line = 1 µm.

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a cheliceral protuberance absent b seta ep approximation and shape of palpcoxal base medial edges: separated; curved frontal lobe a slight indentation of the palp apical lip, with seta v appressed against the lip at the indentation c three parallel ridges on palpcoxal plate, similar to ridges on this plate in Ectomerus sp. cf. E. systenus (Fig. 3.31b)

Fig. 3.30. Gnathosoma of Afromerus lindquisti Meyer, 1990 (Eriophyidae: Cecidophyinae: Colomerini) from Psydrax

livida: a) dorsal view (female); b, c) ventro-lateral views (males); a, b) scale lines = 1 µm; c) scale line = 10 µm.

Chapter 3. Morphology.

119

approximation and shape of palpcoxal base medial edges: separated; slightly curved a b seta ep c frontal lobe three parallel ridges on palpcoxal plate, similar to ridges on this plate in

Afromerus lindquisti (Fig. 3.30c) this structure relatively long in this species; it has an uncertain origin: it may be an extension of the prodorsum anteriad of the prodorsal shield, or it may be an extension of, or contains parts of the subcapitulum and/or bases of the chelicerae

Fig. 3.31. Gnathosoma of Ectomerus sp. cf. E. systenus Meyer, 1990 (Eriophyidae: Cecidophyinae: Colomerini) from

Terminalia sericea: a) dorsal view (probably adult, gender unknown); b) ventral view (female); c) dorso-lateral view

(probably adult, gender unknown); a, c) scale lines = 1 µm; b) scale line = 10 µm.

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120

chelicerae and other gnathosomal stylets and stylet sheath not elevated above palp surface a b approximation and shape of palpcoxal base medial edges: separated; curved cheliceral protuberance absent d c cheliceral retainer e

Fig. 3.32. Gnathosoma of Neserella sp. cf. N. tremae Meyer & Ueckermann, 1989 (Eriophyidae: Cecidophyinae:

Colomerini) from Trema orientalis: a) dorsal view (probably adult, gender unknown); b) dorso-lateral view (immature); c) lateral view (probably adult, gender unknown); d) line drawing of Fig. 3.32b; e) ventral view (female); a, b, d) scale lines

= 1 µm; c, e) scale lines = 10 µm.

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a palp apical lips overlap in repose (when mite is not feeding) seta ep b seta d absent overlapping stylet sheath seta ep basal or proximal part of the dorsal cheliceral stylet, which is probably a modification of the fixed stylet, just before the bulbous cheliceral base broadened, bulbous base of chelicera cheliceral retainer approximation and shape of palpcoxal base medial edges: separated; slightly curved cheliceral protuberance absent probably accessory stylet frontal lobe

Fig. 3.33. (continued on next page). Gnathosoma of Acalitus mallyi (Tucker, 1926) (Eriophyidae: Eriophyinae: Aceriini) from Vangueria infausta subsp. infausta leaf galls: a) dorsal view (probably adult, gender unknown), white arrows indicate droplet-like structures that are probably not part of the mite, but artefacts; b) line drawing of Fig. 3.33a; scale lines = 1 µm.

Chapter 3. Morphology.

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e f g i h flap-like anterior extension of the palpcoxal collar (also see Figs 3.20, 3.21) j the flap-like extension is inconspicuous in slide-mounted specimens, and probably therefore was not mentioned or described in the descriptions of A. mallyi by Tucker

(1926) and Meyer (1990a)

Fig. 3.33. (continued from previous page). Gnathosoma of Acalitus mallyi: e) ventral view (female); f) ventro-lateral view

(female); g) lateral view (female); h) line drawing of Fig. 3.33f; i) line drawing of Fig. 3.33g; j) digital image captured of slide-mounted female specimen, outline of flap extension of coxal plate very unclear, traced with a red stipple line; a knoblike structure in a hollow formed by the anterior edge of the ventral coxal base indicated by the white arrows in f, g, and dashed black arrows in h, i; e, g, i) scale lines = 10 µm; f, h) scale lines = 1 µm; j) scale line = 20 µm.

Chapter 3. Morphology.

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a b cheliceral protuberance c approximation and shape of palpcoxal base medial edges: separated; curved d cheliceral retainer

Fig. 3.34 (continued on next page). Gnathosoma of Aceria lantanae (Cook, 1909) (Eriophyidae: Eriophyinae: Aceriini) from Lantana x camara (hybrid complex) flower galls: a, b) dorsal views (probably adults, gender unknown); c) line drawing of Fig. 3.34a; d) enlargement of cheliceral protuberances in Fig. 3.34b. Scale lines = 1 µm.

Chapter 3. Morphology.

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e g f palp apical lip outer side of tarsus obtusely pointed distally, seta v at apex ventral side of stylet sheath of subcapitulum h

Fig. 3.34. (continued from previous page). Gnathosoma of Aceria lantanae: e) lateral view (female); f) line drawing of

Fig. 3.34e; g, h) ventral views of the same specimen (female); e, f, g) scale lines = 1 µm; h) scale line = 10 µm.

Chapter 3. Morphology.

125

approximation and shape of palpcoxal base medial edges: separated; curved a b cheliceral protuberance absent seta ep appressed to palp surface, and projects convergently anteriad c

Fig. 3.35. Gnathosoma of Aceria ocellatum Meyer & Ueckermann, 1990 (Eriophyidae: Eriophyinae: Aceriini) from

Searsia lancea (previously Rhus lancea) leaf galls: a) dorsal view (probably adult, gender unknown); b) dorsal view

(immature); c) dorso-lateral view (probably adult, gender unknown); a) scale line = 1 µm; b, c) scale lines = 10 µm.

Chapter 3. Morphology.

126

a b c cheliceral protuberance absent d f approximation and shape of palpcoxal base medial edges: separated; slightly curved e

Fig. 3.36. Gnathosoma of Aceria sp. cf. A. dichrostachyia (Tucker, 1926) (Eriophyidae: Eriophyinae: Aceriini) from

Dichrostachys cinerea subsp. and var. unknown: a) dorso-lateral view (probably adult, gender unknown); b) dorso-lateral view (larva); c) line drawing of Fig. 3.36a; d, e) lateral view of the same specimen (female); f) ventral view (female); a, c) scale lines = 10 µm; b, d, e, f) scale lines = 1 µm.

Chapter 3. Morphology.

127

a b lateral extension of stylet sheath relatively long and extensive compared with other species in the present study

(see Fig. 3.20 for terminology) seta d possibly closer to distal margin, than to extended proximal margin of palp genu d c cheliceral retainer seta ep appressed to palp surface, and projects convergently anteriad

Fig. 3.37. Gnathosoma of Aceria sp. cf. A. giraffae Meyer, 1990 (Eriophyidae: Eriophyinae: Aceriini) from Acacia

erioloba: a) dorsal view (probably adult, gender unknown); b) ventro-lateral view (female); c) enlargement of cheliceral protuberances in Fig. 3.37a; d) dorso-lateral view (probably adult, gender unknown); a, b) scale lines = 10 µm; d) scale line = 1 µm.

Chapter 3. Morphology.

128

c d a seta d b seta v seta ep frontal lobe artefacts: (1) cracking up of surface due to disintegration of specimen, and (2) presence of single ice crystals gnathosoma more prognathous e

Fig. 3.38. Gnathosoma of Aceria sp. cf. Aceria sp. nov. (Eriophyidae: Eriophyinae: Aceriini) from Chrysanthemoides

incana: a) dorsal view (probably adult, gender unknown); b) line drawing of Fig. 3.38a, dashed black line indicates length of palpcoxal base; c) lateral view (female); d) ventral view (female); e) ventral view (male); a, b, c, e) scale lines = 1 µm;

d) scale line = 10 µm.

Chapter 3. Morphology.

129

a b c palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum d

Fig. 3.39. Gnathosoma of Aceria sp. nov. females (Eriophyidae: Eriophyinae: Aceriini) from Chrysanthemoides

monilifera subsp. monilifera: a) dorso-lateral view; b) ventro-lateral view; c) lateral view; d) ventro-lateral view of apical tip of the pedipalpi; a, b) scale lines = 10 µm; c, d) scale lines = 1 µm.

Chapter 3. Morphology.

130

a b c d seta ep appressed to palp surface, and projects convergently anteriad e lateral extension of stylet sheath (see Fig. 3.20) palpcoxal collar

(see Fig. 3.20) palpcoxal plate (see Fig. 3.20)

Fig. 3.40. Gnathosoma of Aceria sp. cf. A. proteae Meyer, 1981 (Eriophyidae: Eriophyinae: Aceriini) from Protea caffra subsp. caffra: a) dorsal view (probably adult, gender unknown); b) dorsal view (larva); c) lateral view (female); d, e) ventro-lateral views (females); a, b, e) scale lines = 1 µm; c, d) scale lines = 10 µm.

Chapter 3. Morphology.

131

a cheliceral protuberance b cheliceral retainer enlarged knob-like base of chelicera c d seta d seta v seta ep cheliceral protuberance enlarged knob-like base of chelicera cheliceral retainer frontal lobe

Fig. 3.41. (continued on next page). Gnathosoma of Aceria sp. cf. Aceria sp. nov. (Eriophyidae: Eriophyinae: Aceriini) from Ipomoea batatas var. batatas: a) dorso-lateral view (probably adult, gender unknown); b) dorsal view (probably larva); c) enlargement of cheliceral protuberances in 3.41a; d) line drawing of Fig. 3.41a. White arrows indicate dropletlike structures that are probably not parts of the mites, but artefacts. Scale lines = 1 µm.

Chapter 3. Morphology.

132

e f g palpcoxal plate (”oral plate” of H.H. Keifer) h palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum

Fig. 3.41. (continued from previous page). Gnathosoma of Aceria sp. cf. Aceria sp. nov.: e) dorso-lateral view (male); f) lateral view of basal part of gnathosoma (female); g) ventro-lateral view (female); h) ventral view (female); e, h) scale lines = 10 µm; f, g) scale lines = 1 µm.

Chapter 3. Morphology.

133

a b seta d cheliceral protuberance seta ep c d second seta-like protuberance third extremely small protuberance e palp seta d, positioned closer to the proximal margin of the trochanter-femur-genu segment than usual g f second seta (Fig.

3.42f), possibly homologous to the first protuberance

(Fig. 3.42e) next to seta ep in the

Aceria sp. above seta ep cheliceral retainer

Fig. 3.42. (continued on next page). Gnathosoma of Aceria sp. cf. Aceria sp. nov. (Eriophyidae: Eriophyinae: Aceriini) from Oxalis corniculata: a) dorsal view (probably adult, gender unknown), white arrows indicate seta ep (closest to dorsal exposed parts of the chelicerae), and two protuberances on the side of it; b) line drawing of Fig. 3.42a; c) enlargement of cheliceral protuberances in Fig. 3.42a; d) enlargement of seta ep on the right hand side of the specimen in Fig. 3.42a and the first protuberance alongside it; e) enlargement of seta ep and two protuberances indicated by white arrows in Fig.

3.42a, also here indicated by white arrows; f) seta ep, and seta (still unnamed, but mentioned in the text description) alongside it on the gnathosomal palpcoxal base of Acaphyllisa limitata (drawing from Flechtmann & Etienne, 2001), which might be homologous with the first protuberance alongside seta ep in the Aceria sp. from O. corniculata; g) lateral view (probably adult, gender unknown) with black arrows indicating the first protuberance next to seta ep. Scale lines = 1

µm.

Chapter 3. Morphology.

134

h i seta v flattened dorso-ventrally

Fig. 3.42. (continued from previous page).Gnathosoma of Aceria sp. cf. Aceria sp. nov.: h) ventro-lateral view (male), some detail enhanced with black drawing line to make it more visible; i) ventro-lateral view (male); h) scale line = 10 µm;

i) scale line = 1 µm.

Chapter 3. Morphology.

135

b e c cheliceral protuberance d cheliceral retainer broadened, bulbous base of chelicera f

Fig. 3.43. Gnathosoma of Aceria sp. cf. Aceria sp. nov. (Eriophyidae: Eriophyinae: Aceriini) from Acacia rehmanniana: a) dorso-lateral view (probably adult, gender unknown), short white arrow indicates one of the droplet-like structures which are probably not part of the mite, but artefacts; b) dorso-lateral view (larva), some lines traced in black to make them more clear; c) enlargement of cheliceral protuberances in Fig. 3.43a; d) lateral view (female); e) ventro-lateral view (female), a rounded bump each side laterally on ventral palpcoxal base (indicated by white arrows); f) ventral view (female), a rounded bump each side laterally on ventral palpcoxal base (indicated by white arrows); a, b, d) scale lines = 1 µm; d, f) scale lines = 10 µm.

Chapter 3. Morphology.

136

a b cheliceral protuberance d c seta d cheliceral protuberance seta ep appressed to palp surface, and projects convergently anteriad frontal lobe cheliceral retainer

Fig. 3.44. (continued on next page). Gnathosoma of unknown genus, nr. Aceria (Eriophyidae: Eriophyinae: Aceriini) from

Apodytes dimidiata subsp. dimidiata flower buds: a, b) dorsal views of the same specimen (probably adult, gender unknown); c) line drawing of Fig. 3.44a; d) enlargement of cheliceral protuberances in Fig. 3.44b. Scale lines = 1 µm.

Chapter 3. Morphology.

137

e ff g setae ep lying flat on palp surface, and projecting anteriad, converging trochanter-femur palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum h ventral margin between genu and trochanter-femur curved, probably to facilitate telescoping of apical segments during feeding genu, partly fused to trochanter-femur tibia tarsus palp apical lip division between tibia and tarsus not apparent on surface, they may be fused, or partly fused seta v

Fig. 3.44. (continued from previous page). Gnathosoma of unknown genus, nr. Aceria: e) ventro-lateral view (male); f) dorso-lateral view (probably adult, gender unknown); g) line drawing of Fig. 3.44e; h) ventro-lateral view (female); e, g,

h) scale lines = 1 µm; b) scale line = 10 µm.

Chapter 3. Morphology.

138

a b seta ep erect and projecting convergently anteriad overlapping stylet sheath c seta d d frontal lobe broadened, bulbous base of chelicera palpcoxal base surface fitting across part of the cheliceral base, with largest part of cheliceral retainer obscured by frontal lobe

Fig. 3.45. Gnathosoma of cf. Aceria sp. (Eriophyidae: Eriophyinae: Aceriini) from Cineraria sp. blisters: a) lateral view

(female); b, d) ventral views of the same specimen (female); c) dorsal view (probably adult, gender unknown); a, c) scale lines = 1 µm; b, d) scale lines = 10 µm.

Chapter 3. Morphology.

139

a b seta v palp apical lip tarsus trochanter-femur tibia genu subcapitulum: stylet sheath subcapitulum: palpcoxal plate c d

Fig. 3.46. Gnathosoma of Aceria sp. cf. Aceria sp. nov. (Eriophyidae: Eriophyinae: Aceriini) from Xymalos monospora: a) dorsal view (probably adult, gender unknown); b, c) ventral views of the same specimen (female); lateral view (female);

a, c) scale lines = 10 µm; b, d) scale lines = 1 µm.

Chapter 3. Morphology.

140

b c cheliceral protuberance d

Fig. 3.47. Gnathosoma of Tumescoptes sp. cf. T. dicrus (Eriophyidae: Phyllocoptinae: Acaricalini) from Phoenix reclinata:

a) ventro-dorsal view (female); b) bifurcate setae d enlarged to show tiny side branch (probably adult, gender unknown);

c) enlargement of cheliceral protuberance in Fig. 3.47a; d) venro-lateral view (female). Scale lines = 1 µm.

Chapter 3. Morphology.

141

a b c seta ep stylets, probably covered by cheliceral sheath seta d palp apical lip palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum half circular ridge palpcoxal base trochanter-femur subcapitulum genu tibia tarsus seta v

Fig. 3.48. (continued on next page). Gnathosoma of Calacarus sp. (Eriophyidae: Phyllocoptinae: Calacarini) from Searsia

lancea (previously Rhus lancea): a) lateral view (female); b) dorso-lateral view (female); c) line drawing of Fig. 3.48a.

Scale lines = 10 µm.

Chapter 3. Morphology.

142

d e ff

Fig. 3.48. (continued from previous page). Gnathosoma of Calacarus sp.: d) ventral view (female); e) ventro-lateral view

(female); f) line drawing of “palpcoxal plate area” of Fig. 3.48d, *names for different areas are preliminary (also see Fig.

3.20). Scale lines = 10 µm.

Chapter 3. Morphology.

143

a b

Fig. 3.49. Gnathosoma of Calacarus sp. (Eriophyidae: Phyllocoptinae: Calacarini) from Faurea rochetiana: a, b) lateral view of the same specimen (probably adult, gender unknown). Scale lines = 10 µm.

a b c d

Fig. 3.50. Gnathosoma of Calacarus sp. (Eriophyidae: Phyllocoptinae: Calacarini) from Psydrax livida: a) dorsal view

(probably adult, gender unknown), in vagrants, like this Calacarus sp., the frontal lobe obscures the gnathosoma which is also usually more hypognathous in these species, in dorsal view; b) lateral view (probably adult, gender unknown); c, d) ventro-lateral views of the same specimen (female); a, b, c) scale lines = 10 µm; d) scale line = 1 µm.

Chapter 3. Morphology.

144

a c gnathosoma obscured by frontal lobe in dorsal view b cheliceral retainer seta ep extrusion of possibly several gnathosomal stylets, closely fitted against each other, from the stylet sheath subcapitulum: stylet sheath d e

Fig. 3.51. Gnathosoma of a Shevtchenkella sp. cf. S. lividae (Meyer, 1990) (Eriophyidae: Phyllocoptinae: Tegonotini) from

Psydrax livida: a) gnathosoma obscured by frontal lobe in dorsal view (probably adult, gender unknown); b) dorso-lateral view (male); c) ventral-dorsal view (female), note extrusion of possibly several gnathosomal stylets, closely fitted against each other, from the stylet sheath; d) ventro-lateral view male; a, b, d) scale lines = 10 µm; c, e) scale lines = 1 µm.

Chapter 3. Morphology.

145

a b c palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum

Fig. 3.52. Gnathosoma of Shevtchenkella sp. cf. S. rhusi (Meyer, 1990) (Eriophyidae: Phyllocoptinae: Tegonotini) from

Searsia lancea (previously Rhus lancea): a) frontal lobe largely obscures gnathosoma in dorsal view (probably adult, gender unknown); b) dorso-lateral view (probably adult, gender unknown); c) ventro-lateral view (female); a, c) scale lines = 10 µm; b) scale line = 1 µm.

a palpcoxal base segment is a continuous structure dorsoventrally, and particularly ventrally it forms part of the subcapitulum b

Fig. 3.53. Gnathosoma of Neoshevtchenkella or Shevtchenkella sp. (with wax) (Eriophyidae: Phyllocoptinae: Tegonotini) from Celtis africana: a) dorso-ventral view (female); b) lateral view (female). Scale lines = 10 µm.

Chapter 3. Morphology.

146

cc a b d cheliceral protuberances e

Fig. 3.54. Gnathosoma of cf. Calepitrimerus sp. (Eriophyidae: Phyllocoptinae: Phyllocoptini) from Celtis africana: a, b) ventral views of the same specimen (female); c) dorso-lateral view (female); d) enlargement of cheliceral protuberances in

Fig. 3.54c; e) dorso-lateral view (probably adult, gender unknown); a, e) scale lines = 1 µm; b, c) scale lines = 10 µm.

Chapter 3. Morphology.

147

seta ep c a b d

Fig. 3.55. Gnathosoma of Cecidodectes euzonus Nalepa, 1917 (Eriophyidae: Phyllocoptinae: Phyllocoptini) from Trema

orientalis: a) dorso-lateral view (probably adult, gender unknown), dashed black line indicates length of palpcoxal base;

b) ventro-lateral view (female); c) lateral view (probably adult, gender unknown); d) ventro-lateral view (female); a) scale line = 1

µm; b, c, d) scale lines = 10 µm.

Chapter 3. Morphology.

148

a cheliceral protuberance b c e f this structure seems to be a seta or something similar inserted on a tubercle, similar to a setal tubercle, but this is inconclusive d cheliceral protuberance on the right is larger than the protuberance on the left

Fig. 3.56. Gnathosoma of cf. Phyllocoptes sp. (Eriophyidae: Phyllocoptinae: Phyllocoptini) from Anthocleista grandiflora:

a) dorsal view (probably adult, gender unknown); b) enlargement of the cheliceral protuberances in Fig. 3.56a; c) lateral view (female); d) line drawing of cheliceral protuberances enlarged in Fig. 3.56b; e, f) ventral views (females); a, c, f) scale lines = 1 µm; e) scale line = 10 µm.

Chapter 3. Morphology.

149

a cheliceral protuberance seta ep b seta ep c seta d stylet sheath seta ep cheliceral retainer

Fig. 3.57. (continued on next page). Gnathosoma of Tergilatus sparsus Meyer & Ueckermann, 1995 (Eriophyidae:

Phyllocoptinae: Phyllocoptini) from Portulacaria afra: a) dorsal view (female); b) dorso-lateral view (larva), short white arrow indicates droplet-like structure that is probably not part of the mite, but an artefact; c) enlargement of cheliceral protuberances in Fig. 3.57a; d) line drawing of Fig. 3.57b; a) scale line = 10 µm; b, d) scale lines = 1 µm.

Chapter 3. Morphology.

150

e g f

Fig. 3.57. (continued from previous page). Gnathosoma of Tergilatus sparsus: e) ventro-lateral view (male); f) ventral view (immature, stage unknown); g) ventro-lateral view (female). Scale lines = 10

µm.

frontal lobe seta ep

Fig. 3.58. Gnathosoma of possibly Aculops or Metaculus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini) from

Anthocleista grandiflora: dorso-lateral view (probably adult, gender unknown). Scale line = 10

µm.

Chapter 3. Morphology.

151

a frontal lobe cheliceral protuberance b c d e

Fig. 3.59. Gnathosoma of Aculus sp. cf. Aculops lycopersici (Eriophyidae: Phyllocoptinae: Anthocoptini) from Physalis

peruviana: a) dorso-ventral view (female); b) enlargement of cheliceral protuberances in Fig. 3.59a; c) lateral view

(female); d) dorso-lateral view (female); ventral view (female); a, d, e) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

152

a cheliceral protuberance b frontal lobe setae ep cheliceral protuberance cheliceral protuberance c d e

Fig. 3.60. Gnathosoma of cf. Aculus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini) from Acacia burkei: a, c, d) lateral views of different areas and enlargements of the same female specimen; b) line drawing of the cheliceral protuberances in

Fig. 3.60a (enlarged in Fig. 3.60d); e) dorso-lateral view, basal part of gnathosoma obscured by frontal lobe (probably adult, gender unknown). Scale lines = 1 µm.

Chapter 3. Morphology.

153

c a b seta ep erect and projecting convergently anteriad cheliceral protuberance frontal lobe d e f tarsus with ridge/lobe-like buldge at seta v base g h

Fig. 3.61. Gnathosoma of cf. Aculus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini) from Lantana trifolia: a) dorsolateral view (probably adult, gender unknown); b) dorsal view (probably adult, gender unknown); c) basal part, dorsolateral view (probably adult, gender unknown), short white arrow indicates droplet-like structure that is probably not part of the mite, but an artefact; d) enlargement of cheliceral protuberances in Fig. 3.61b; e) distal part, ventro-lateral view

(female); f) palpcoxal plate region, ventro-lateral view (female, same specimen as in Fig. 3.61e); g) distal part, lateral view (female); h) basal part, lateral view (female); a, b, c, e, h) scale lines = 1 µm; f, g) scale lines = 10 µm.

Chapter 3. Morphology.

154

b a seta ep secreted wax seta ep erect and projecting convergently anteriad

Fig. 3.62. Gnathosoma of cf. Aculus sp. or possibly an immature of Quantalitus (Eriophyidae) from Rothmannia

capensis: a) dorsal view, frontal lobe obscures most of gnathosoma (possibly immature); b) lateral view (immature). Scale lines = 10 µm.

Chapter 3. Morphology.

155

a b c seta ep erect and projecting convergently anteriad d

Fig. 3.63. Gnathosoma of Costarectus zeyheri Meyer & Ueckermann, 1995 (Eriophyidae: Phyllocoptinae: Anthocoptini) from Dovyalis zeyheri: a) dorso-lateral view (adult, probably female); b) dorso-lateral view (male); c) lateral view

(female); d) ventro-lateral view (female), short white arrow indicates droplet-like structure that is probably not part of the mite, but an artefact; a, b, d) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

156

a cheliceral protuberance seta ep b c d frontal lobe e artefact: ice formation on specimens f palp apical lip seta v tarsus tibia genu trochanter-femur subcapitulum: stylet sheath subcapitulum: palpcoxal plate g

Fig. 3.64. Gnathosoma of Meyerella bicristatus (Meyer, 1989) females (Eriophyidae: Phyllocoptinae: Anthocoptini) from

Mystroxylon aethiopicum: a, c, f) ventro-dorsal views of the same specimen, with cheliceral protuberances in Fig. 3.64a enlarged in c and further enlarged in f; b) ventral view; d) lateral view; e) ventro-lateral view; g) line drawing of Fig.

3.64e; a, b, c, e) scale lines = 1 µm; d) scale line = 10 µm.

Chapter 3. Morphology.

157

d a cheliceral protuberance wax secreted by the mite, possibly mixed with dirt b seta ep erect and projecting convergently anteriad c

Seta d bended, forming a sharp corner that may be the start of developing a second branch of the seta. Eventually it may develop into a bifurcate seta. This modification may arise to facilitate the seta to press down more sturdy and stable on a substrate. It may assist the palp lips to anchor on the plant substrate when the apical palp segments telescope and the gnathosomal stylets are pushed into the plant cell for feeding. It may also help in generally balancing and stabilizing the mite.

There doesn’t seem to be a side-branch at the bend of setae d, otherwise it is extremely tiny and under-developed.

e

Fig. 3.65. (continued on next page). Gnathosoma of possibly a new genus nr. Costarectus (Eriophyidae: Phyllocoptinae:

Anthocoptini) from Mystroxylon aethiopicum: a) dorso-lateral view (probably adult, gender unknown); b, e) lateral views of the same specimen (male); c) enlargement of cheliceral protuberances in Fig. 3.65a; d) dorsal view to show the shape of the dorsal pedipalp genual setae (setae d) (probably adult, gender unknown); a, d, e) scale lines = 1 µm; b) scale line =

10 µm.

Chapter 3. Morphology.

158

f g h

Fig. 3.65. (continued from previous page). Gnathosoma of possibly a new genus nr. Costarectus: f) ventro-lateral view

(male); g) ventral view (male); h) line drawing of Fig. 3.65g. Scale lines = 10 µm.

b a

Fig. 3.66. Gnathosoma of possibly a new genus nr. Tetra (Eriophyidae: Phyllocoptinae: Anthocoptini) from Protea caffra subsp. caffra: a) dorso-lateral view (probably adult, gender unknown); b) ventro-lateral view (female). Scale lines = 10

µm.

Chapter 3. Morphology.

159

c a frontal lobe d b seta ep erect and projecting convergently anteriad cheliceral protuberance f e

Fig. 3.67. Gnathosoma of possibly a new genus nr. Mesalox (Eriophyidae: Phyllocoptinae: Anthocoptini) from Apodytes

dimidiata: a) dorsal view (probably adult, gender uknown); b) lateral view (female); c) ventro-dorsal view (female); d) ventro-lateral view (female); e) enlargement of the cheliceral protuberances in Fig. 3.67a; f) ventral view (male); a, c) scale lines = 1 µm; b, d, f) scale line = 10 µm.

Chapter 3. Morphology.

160

a b c bifurcate seta d

Fig. 3.68. Gnathosoma of Porosus monosporae Meyer & Ueckermann, 1995 (Eriophyidae: Phyllocoptinae: Anthocoptini) from Xymalos monospora: a) ventro-lateral view (female); b) ventral view (female); c) ventro-lateral view (male); a, b) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

161

a b

Fig. 3.69. Gnathosoma of Tegolophus sp. cf. T. orientalis Meyer, 1990 (Eriophyidae: Phyllocoptinae: Anthocoptini) from

Trema orientalis: a) ventro-lateral view (female); b) lateral view (female). Scale lines = 10 µm.

a b cheliceral protuberance c wax secreted by the mite, possibly mixed with dirt

Fig. 3.70. (continued on next page). Gnathosoma of Tetra retusa Meyer, 1992 (Eriophyidae: Phyllocoptinae:

Anthocoptini) from Bauhinia galpinii: a) dorso-lateral view (probably adult, gender unknown); b) enlargement of cheliceral protuberances in Fig. 3.70a; c) dorsal view (probably adult, gender unknown). Scale lines = 10 µm.

Chapter 3. Morphology.

162

g d e f cheliceral protuberance h

Fig. 3.70. (continued from previous page). Gnathosoma of Tetra retusa: d) ventro-lateral view (female); e) lateral view

(female); f) dorso-lateral view (larva); g) ventral view (female); h) ventral view (male); d, e, f) scale lines = 1 µm; g, h) scale lines = 10 µm.

Chapter 3. Morphology.

163

a cheliceral protuberance b d c e

Fig. 3.71. Gnathosoma of Tetraspinus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini) from Chrysanthemoides monilifera subsp. monilifera: a) dorso-ventral view (female); b) enlargement of cheliceral protuberances in Fig. 3.71a; c, d) lateral views (females); e) dorso-lateral view (probably adult, gender unknown); a, c, d) scale lines = 10 µm; e) scale line = 1

µm.

Chapter 3. Morphology.

164

a b c cheliceral protuberance d e

Fig. 3.72. Gnathosoma of cf. Tetraspinus sp. (Eriophyidae: Phyllocoptinae: Anthocoptini) from Faurea rochetiana: a) dorso-lateral view (probably adult, gender unknown); b) lateral view (female); c) dorso-ventral view (female); d) lateral view (female); e) enlargement of cheliceral protuberances; a) scale line = 1 µm; b, c, d) scale lines = 10 µm.

Chapter 3. Morphology.

165

a b c d seta ep appressed to palp surface and projecting convergently anteriad

Fig. 3.73. (continued on next page). Gnathosoma of a possibly new worm-like genus (Eriophyidae: Eriophyinae?:

Aceriini?) from Faurea rochetiana: a) dorsal view (probably adult, gender unknown), the black arrow indicates the slight ridge shaped inner edge of the palp trochanter-femur; b) dorso-lateral view (probably adult, gender unknown); c) dorsolateral view (probably adult, gender unknown), the black arrow indicates the slight ridge shaped inner edge of the palp trochanter-femur; d) line drawing of Fig. 3.73a, dashed black line indicates length of palpcoxal base. Scale lines = 1 µm.

Chapter 3. Morphology.

166

f h g

Fig. 3.73. (continued from previous page). Gnathosoma of a possibly new worm-like genus (Eriophyidae: Eriophyinae?:

Aceriini?): f) ventral view (female); g) ventro-lateral view (male); h) line drawing of Fig. 3.73f. Scale lines = 1 µm.

Fig. 3.74. Gnathosoma of an unknown genus (could not be identified) (Eriophyidae: Phyllocoptinae?) from Ekebergia

capensis: ventral view (male). Scale line = 10 µm.

Chapter 3. Morphology.

167

c f a b cheliceral protuberance cheliceral protuberances seta ep erect d e g seta v flattened

Fig. 3.75. Gnathosoma of a possibly new genus in the Phyllocoptinae or Cecidophyinae (Eriophyidae) from Acacia

burkei: a) lateral view (possibly nymph); b) same specimen as in Fig. 3.75a, enlargement of cheliceral protuberances; c, f) ventral views of the same specimen (female); d) dorsal view, gnathosoma obscured by frontal lobe (probably adult, gender unknown); e) line drawing of Fig. 3.75g; g) lateral view (female) with dorso-ventrally flattened and oval shaped setae v; a,

d, f) scale lines = 10 µm; b, c, g) scale lines = 1 µm.

Chapter 3. Morphology.

168

a e c d seta ep erect f b

Fig. 3.76. Gnathosoma of Phyllocoptes sp. (Phyllocoptinae) or new genus (Cecidophyinae) from Dovyalis zeyheri: a) dorsal view, basal part of gnathosoma obscured by frontal lobe (probably adult, gender unknown); b) ventral view (male);

c) lateral view of basal part of gnathosoma (female); d) ventro-lateral view (female); e) lateral view of distal part of gnathosoma (female); f) dorso-lateral view (larva); a, d) scale lines = 1 µm; b, c, e, f) scale lines = 10 µm.

Chapter 3. Morphology.

169

a cheliceral protuberance b e frontal lobe c seta ep f d

Fig. 3.77. Gnathosoma of a probably new genus (Eriophyidae, subfamily uncertain) from Cussonia sp. flowers: a) dorsolateral view (probably adult, gender unknown); b, d) ventro-lateral views of the same specimen (female); c) enlargement of cheliceral protuberances in Fig. 3.77a; e) lateral view (female); f) ventral view (male); a, d, e, f) scale lines = 10 µm;

b) scale line = 1 µm.

Chapter 3. Morphology.

170

a b e seta ep erect c d seta v f

ep

seta v g

Fig. 3.78. Gnathosoma of Diptilomiopus apobrevis sp. nov. (Diptilomiopidae: Diptilomiopinae) from Apodytes dimidiata:

a) dorso-lateral view (probably adult, gender unknown); b) ventro-dorsal view (female); c) dorso-lateral view (larva); d) ventro-lateral view (female); e) lateral view, basal part (possibly nymph, or male); f) ventro-lateral view, apical part

(female); g) ventral view (female). Scale lines = 10 µm.

Chapter 3. Morphology.

171

a proximal edge of overlapping stylet sheath b cheliceral sheath and stylets extending significantly above palp gnathosoma more hypognathous c seta ep erect d e f seta v

Fig. 3.79. Gnathosoma of Diptilomiopus faurius sp. nov. (Diptilomiopidae: Diptilomiopinae) from Faurea rochetiana: a) dorsal view (probably adult, gender unknown); b) lateral view (female), dashed black line indicates length of palpcoxal base; c) dorso-lateral view, basal part (female); d, e) ventro-lateral views of the same specimen (female); lateral view

(distal part of gnathosoma); a, b, d) scale lines = 10 µm; c, e, f) scale lines = 1 µm.

Chapter 3. Morphology.

172

a seta ep erect b c d seta v

Fig. 3.80. Gnathosoma of unidentified species (genus and species could not be identified) (Diptilomiopidae:

Diptilomiopinae) from Xymalos monospora: a) dorso-lateral view (probably adult, gender unknown); b) ventro-lateral view (female); c) ventral view (male); d) lateral view (female); a, b, d) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

173

a b c d e seta ep erect f seta v g

Fig. 3.81. Gnathosoma of probably a new genus nr. Dacundiopus (Diptilomiopidae: Diptilomiopinae), from Mystroxylon

aethiopicum: a) dorsal view (probably adult, gender unknown); b) ventro-dorsal view (female); c) dorsal view (immature);

d, e) lateral views (females); f) ventral view (female); ventro-lateral view (female); a, b, d, e, f, g) scale lines = 10 µm; c) scale line = 1 µm.

Chapter 3. Morphology.

174

a c e seta v f b d seta ep erect frontal lobe

Fig. 3.82. Gnathosoma of Rhynacus sp. cf. Rhynacus sp. nov. (Diptilomiopidae: Diptilomiopinae) from Dovyalis zeyheri:

a, b) dorso-lateral view and enlargement of the basal area respectively of the same specimen (probably adult, gender unknown); c, e) lateral view and enlargement of the distal part respectively of the same specimen (male); d) dorso-lateral view (female); f) ventro-lateral view (male); a, c, d, f) scale lines = 10 µm; b, e) scale lines = 1 µm.

Chapter 3. Morphology.

175

a b seta d seta d? (not clear in SEM image whether it is a leg seta lying across the palp or seta d) cc cheliceral sheath palp cheliceral stylet d possibly a special interlocking system between the chelicerae and palpi; the structure could not be correctly interpreted in the line drawing

Fig. 3.83. Gnathosoma of probably a new genus (Eriophyidae) from Searsia lancea (previously Rhus lancea) leaf blisters: a) dorsal view (probably adult, gender unknown); b) ventral view (immature); c) preliminary attempt at a line drawing (which is probably still wrong and incomplete, because the SEM images that could be obtained from this species were very unclear, probably due to a sticky substance covering the mites) of the dorsal view of the gnathosoma, from Fig.

3.83a; d) lateral view (probably adult, gender unknown); a, c, d) scale lines = 1 µm; b) scale line = 10 µm.

Chapter 3. Morphology.

176

a c seta ep erect b frontal lobe d e f

Fig. 3.84. Gnathosoma of unidentified morphospecies 2 (Eriophyoidae: Eriophyidae or Phytoptidae, but it is probably

Eriophyidae) from green fruit of Anthocleista grandiflora: a) dorso-lateral view (probably adult, gender unknown); b) dorsal view (larva); c, f) lateral views of the same specimen (probably adult, gender unknown); d) ventral view (female);

e) ventral view (male); a, b, c) scale lines = 1 µm; d, e, f) scale lines = 10 µm.

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a b c seta ep erect frontal lobe d e f seta v

Fig. 3.85. Gnathosoma of unidentified species (genus and species could not be identified) (Eriophyoidea) from

Sideroxylon inerme subsp. inerme: a) dorso-lateral view (probably adult, gender unknown); b) dorso-lateral view (female); c) ventro-lateral view (female); d) ventro-lateral view (female); e) lateral view (female); f) ventro-lateral view (female); a,

b, c) scale lines = 1 µm; d, e, f) scale lines = 10 µm.

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3.6

GENERAL DISCUSSION

Similar to other organisms, the quality of the systematics of the Eriophyoidea is associated with the quality of the morphological character descriptions of its taxa. Additional information such as molecular, biological and ecological data can also be incorporated into studies. The quality of eriophyoid systematics also depends on the quality of specimens studied and the observations that are possible. These depend on the collection, preparation, mounting and storage of specimens, and the technology and techniques used to study the specimens.

In practice, there are various short-comings in the systematics of the Eriophyoidea which are almost solely based on morphological information obtained from light microscopic studies of slide-mounted specimens. Often, descriptions and drawings do not achieve the required standard and do not convey taxonomically important characteristics. Much of the weakness in published morphology is caused by the quality and standard of slide-mounted specimens and the quality of their study (Amrine & Manson, 1996; De Lillo et al., 2010). To begin with, the quality of morphological descriptions and systematics of eriophyoid mites can be improved to a large extent, at least for classification and identifications, by improving slide-mounting and description of slidemounted specimens.

There are, however, inherent inadequacies in light microscopic studies of slide-mounted specimens. Additionally, even when using optimal slide-mounting techniques and study of such specimens, there are problems with standardization of results (De Lillo et al., 2010). Descriptions based on the study of slide-mounted specimens, however, are in essence useful and robust. Some eriophyoid researchers such as E. De Lillo, J.W. Amrine Jr. and V.G. Shevchenko (pers. comm.), strongly advise that the status quo of obtaining the core taxonomic description solely from slidemounted specimens, should be retained.

There are, indeed, many advantages to the conventional practice in the systematics of the

Eriophyoidea, namely:

A large amount of descriptive data are already documented and available;

Some published descriptions are of slide-mounted material that is not available anymore, including type material. For these, the only representation of the taxon is the description

(De Lillo et al., 2010). An attempt can be made to re-collect these taxa for re-descriptions from slide-mounted specimens, as well as incorporating other techniques of study, such as

SEM, but this sets additional problems. As a result there are no characters described for these species to compare with SEM observations on other species;

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The characters and character states are relatively uncomplicated and easily observable;

The classification and identification of known eriophyoid species are largely possible using the present set of characters and descriptions and their associated identification keys; and

Probably most importantly, the slide-mounting technique is reasonably cheap and simple, and equipment for study of slide-mounted specimens is at least available to eriophyoid taxonomists worldwide.

According to some eriophyoid taxonomists, morphological information from SEM studies should not be extensively used and as an obligation incorporated in the systematics and particularly the practical taxonomy of the Eriophyoidea. Unfortunately, the study of slide-mounted eriophyoid specimens has inherent inadequacies and problems that cannot be totally rectified with improved techniques and study. These are demonstrated in part I of present study and briefly entail:

Structures are viewed in two-dimensions and depth and three-dimensional images of structures are formed by the interpretation of the observer, and is subject to error;

Phase contrast light microscopy, necessary to study eriophyoid specimens, causes a light halo around specimens and this obscures some detail;

The size of many eriophyoid morphological structures is at the limits of the resolution of light microscopy. The margin of error in the current descriptions based on light microscopy is too large to be acceptable in phylogenetic studies (see Chapter 4). This may be due to poor descriptions, but can also partly be attributed to the inability to observe precise detail when using light microscopy; and

Slide-mounting causes some artefacts which can be alleviated by using mounting methods that will cause the least artefacts in taxonomically important characters such as the dorsal shield pattern (Denizhan et al., 2008). These alternative methods have their own problems, and it may even be disputed which method will offer the best results for the comparison and identification of specimens. The lack of representation of exact morphology will not always be a problem for identification, because the purpose is mainly to compare certain characters, even if they are incorrectly described, as long as these artefacts are robust, stable and roughly standardized. Such erroneous data, however, are unacceptable for phylogenetic studies (see Chapter 4).

Studying specimens with electron microscopy provides higher resolution and three-dimensional images and can be superior to light microscopy and can improve and alleviate most short-comings

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with light microscopic studies of slide-mounted specimens. SEM studies of eriophyoid mites are, on the other hand, not without inadequacies, limitations and problems of their own such as:

SEM facilities in general are not readily available. In comparison with studying slidemounted specimens with light microscopy, SEM studies are cumbersome, expensive, complicated, time-consuming and unavailable to many researchers worldwide who are studying eriophyoid systematics.

Employing those techniques that may contain the least artefacts, such as cryo-SEM, are even more complicated than conventional SEM and require special SEM equipment and special skills. These skills and equipment are scarce, and probably represent the major constraint facing the incorporation of SEM studies in the systematics of the Eriophyoidea.

Even the SEM research undertaken in the present study may not be able to continue due to funding and easy availability of SEM facilities; and

Specimens prepared for and studied with SEM are not always without artefacts. The amount of distortion and artefacts in specimens are, similar to slide-mounting of specimens, dependent on various factors of which the choice of SEM technique, quality of equipment, and experience and skill of the person preparing and studying the specimens are the most noteworthy. The choice of SEM technique should take into consideration the aim of the SEM study. Elimination of shape distortion, and improvement on observing ultra-structural detail, and general representation of true morphology, as found in live specimens, are the main aims. Some SEM techniques (including conventional techniques) may cause shrinking and even more severe shape distortion than what is found in slidemounted specimens. In many cases, the quality of SEM images is inferior to line drawings, particularly caused by shrinking of specimens and sub-standard imagecapturing. Some minute details can, however, still be successfully studied in such images, depending on the quality of resolution and contrast, but studying shape and relative positions of structures is not reliable when any kind of appreciable distortion occurred.

In the present study, the results of the SEM study were not always satisfactory: surface ice could not always be entirely removed; material often degraded after prolonged examination; and some mites intact on plant pieces were washed off during sample preparation in the nitrogen slush. These were mostly caused by the equipment available for the study, and are not inherent to optimal utilization of the cryo-SEM technique. The use of a field emission SEM with cryo-attachment will enhance results (Wergin et al.,

2000), especially for the resolution of fine-structure such as specialized setae, and will

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prevent some of the artefacts experienced (Achor et al., 2001), but this option was not available for the present study;

Not all morphological information necessary for the classification and identification of eriophyoids is available from one specimen when studied with SEM, because all aspects of it cannot be observed as is possible with slide-mounted specimens. In the present study, for instance, the gender, and sometimes even the life stage of specimens in dorsal view could not be determined, and similarly, the dorsal and some lateral characteristics of specimens in ventral view could not be studied. Unfortunately, the cryo-stage of the SEM available could not be tilted. The classification and identification of eriophyoid mites also include the evaluation of internal structures, such as the internal female genitalia, and without this information from slide-mounted specimens, specimens studied with SEM cannot always be identified;

There are frequently not enough specimens available from a collection to incorporate SEM studies, especially when it is combined with light microscopic studies. The manner in which, for example, the cryo-technique for the present study was done, specimens studied with the SEM were inevitably destroyed after one continuous study session. This meant that there was only one change per SEM session to obtain clear and useful images;

Another practical and important problem with published SEM images, although it may at first seem to be a minor problem, is the frequently poor reproduction of printed SEM images, especially when the original article is not available and the article must be obtained through inter-library system which usually provides inferior electronic or photocopied versions of the original publication. In many instances, the SEM images are rendered obscure and unusable, far worse than ever experienced with line drawings. In the present study, for instance, this turned out to be a real constraint. SEM images published in several photocopied articles obtained for present study were not usable (e.g., Fig. 3.86).

In present study, it was in many such instances not possible to obtain the original SEM images or at least scanned versions of the published printed images. Even the original images, however, may be of poor quality; and

Another problem is the enlargement at which SEM images are presented. For example, despite control over the size of the images on paper in the present study, observations for writing-up the information were usually made on images viewed on screen, where images can be interactively enlarged to the limit of usable resolution. Less clear and smaller paper printed versions (also necessary in the present study), make the observation of particularly smaller detail difficult, ambiguous or impossible. These limitations will be drastically improved in future, with an increase in the use of electronic-capturing and

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distribution and when paper format will be supplemented or replaced by electronic versions of articles, including published SEM images.

Although SEM images have been sporadically used in descriptions of new eriophyoid taxa to enhance light microscopic studies, additional morphological data from SEM studies have hardly been incorporated into eriophyoid systematics. SEM images and descriptive morphological data from them are not seriously advocated, neither compulsory for describing new taxa. Comprehensive comparative morphological studies utilizing SEM, with focus on use in systematics, are few and limited in scope.

Understandably, there are reservations about incorporating morphological information from SEM studies in the classification and identification of eriophyoids, especially because SEM facilities are not readily available worldwide. Some authors went as far as basing entire descriptions on even inadequate SEM images (e.g., Huang, 1992). This practice was condemned by Amrine (1996).

The addition of SEM studies to enhance eriophyoid descriptions based on slide-mounted specimens and including detailed descriptive line drawings are propagated, but basing the description of eriophyoid taxa exclusively on SEM studies is not advised (Amrine et al., 2003; De

Lillo & Skoracka, 2010). It is concurred in the present study that descriptions should not be based exclusively on SEM studies, and particularly not when they are not up to standard. Therefore, light microscopy and line drawings should remain the basis for practical identification and identification keys for the time being.

Nevertheless, although morphological data used in taxon descriptions is used for classification and identification which are frequently more practical applications, it still remains a scientific study of the group. Results of morphological studies should represent the actual morphology of life specimens as closely as possible. Artefacts, mistakes in observations and insufficient detail for application and analyses of the data should be avoided at all costs. This will improve all aspects of eriophyoid systematics. In a phylogenetic study, for example, flawed data can result in wrong hypotheses of groupings and relationships between taxa. Scientific study of a group of organisms must not be constrained by the practical applications and problems with infrastructure.

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a b c d

Fig. 3.86. Examples of loss of quality of SEM images of species in the current study, in the publishing and photocopying processes, all printed images scanned with the same scanner in Grayscale at a resolution of 200 dpi, and saved as *.tiff: a) original printed image Fig. 6, p. 232 in Huang (1992); b) photocopy of image received from library, before the original reprint was obtained; c, d) photocopies of SEM images (Plate 1 image A and B here c and d alternatively) originally published on p. 441 in Chandrapatya & Boczek (1991b), original article / reprint or original SEM images not yet obtained.

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It has been confirmed and demonstrated in the present study that the morphological study of eriophyoid specimens incorporating the most appropriate SEM techniques such as cryo-SEM, is in many respects scientifically superior to light microscopic study of slide-mounted specimens.

Despite some problems, the results from the SEM study were satisfactory and contributed considerable amounts of new data. The present study indicates new features not previously reported, or not seen in eriophyoid mites with such clarity of detail. The SEM images also simplify or sometimes clarify the division of structures into homologous substructures for determining primary homologies between characters and character states. The determination of the exact area and structures constituting the so-called basal and distal area of the female genital coverflap, the relative position, and the precise description of these, are examples of this.

In the present study, it was also shown that in the Eriophyoidea too few systematically informative characters are available, particularly for phylogenetic studies (see Chapter 4). To partly alleviate this problem, molecular and other data such as biological and ecological data could also be utilized. Although sound morphological data in these studies are essential, it is also essential to test information from other data sets (that may also have their own problems and limitations), in order to increase information available for phylogenetic studies (Hillis & Wiens, 2000; Jenner,

2004). The comparative study of the gnathosoma of the species included in the present study demonstrated that there are many “new” morphological structures available that may be of systematic value. SEM images can also be duplicated and stored and archived in separate international mite collections in addition to slide-mounted material and other collections of eriophyoid mites, such as dry collections, to accompany and represent type-specimens which will be lost over time.

Aspects that still need discussion and clarification include how much SEM studies can or should contribute to improve the systematics of the Eriophyoidea, and to what extent morphological information that is obtained from SEM studies that may sometimes not be observable in slidemounted specimens, should be incorporated into eriophyoid systematics, taking into account the problems and limitations of SEM studies in eriophyoid research.

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The investigation and testing of new techniques for morphological study are not just confined to the SEM, TEM and light microscopic techniques discussed in this chapter. Numerous modifications for electron and light microscopy have been published, and new equipment is available and more powerful computer technology contributes to these (Alberti & Nuzzaci, 1996).

Eriophyoid taxonomists should continuously investigate these developments for possible improvement of morphological studies of the eriophyoids, since this aspect is such an important part of the systematics of this group.

3.7

CONCLUSIONS

While undertaking the research for this chapter on morphology, as well as coding characters states for phylogenetic analyses in Chapter 4, the importance of using the best techniques for slidemounting of specimens as an important aspect of improving the morphological study of eriophyoid mites (De Lillo et al., 2010) became increasingly clear. These techniques used to date in mounting of specimens in South Africa must be improved. Apart from this, it is clear from the present study that many artefacts are present in slide-mounted specimens, and there are limitations inherent in light microscopy of these specimens that cannot be enhanced and rectified by improving these techniques, and these inadequacies are already built into eriophyoid descriptions and classifications.

Cryo-SEM is a technique that offers excellent improvement to morphological studies, and seems to cause the least artefacts to specimens, and enhances their study. Information from SEM studies not only improved on and rectified information from light microscopic studies and resultant descriptions, but additionally provided a surprisingly large number of new structures that have not been previously reported, that may be of use in systematics. This increase in characters is essential for phylogenetic studies of the Eriophyoidea, and will also improve conventional taxonomy.

Information from SEM studies additionally improves the information and clarity of morphological characters to such a degree that it will aid in the improvement of the identification and delimitation of characters and character states which is also urgently needed in eriophyoid systematics. For all these reasons, the inclusion of SEM studies should not just be a mere enhancement of primary light microscopic studies for taxon descriptions. Morphology studied with SEM should be seriously and routinely incorporated into descriptions of taxa, and making it a requirement in some instances should be considered. The inclusion of SEM studies is compulsory for the description of many nematode groups, largely implemented by peer review practices, and a description will hardly be accepted for publication if these are not included without acceptable reasons (M. Marais,

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pers. comm.

). Numerous phylogenetic studies in spiders are also extensively incorporating information from SEM studies.

In reality, however, SEM facilities are not readily and widely available worldwide. Consequently, morphological information from SEM studies cannot be solely incorporated in the practical description, classification, differentiation and identification of eriophyoid mites, without concurrent and corroborating usable character states from slide-mounted specimens. This is similar to the situation with information from molecular studies.

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