Tegopalpus conicus Womersley, 1940

Beard, Jennifer J., Seeman, Owen D. & Bauchan, Gary R., 2014, Tenuipalpidae (Acari: Trombidiformes) from Casuarinaceae (Fagales), Zootaxa 3778 (1), pp. 1-157 : 128-141

Tegopalpus conicus Womersley, 1940

( Figs 107–123 )

Tegopalpus conicus Womersley, 1940: 242 , fig. 4.

Tegopalpus conicus, Smiley et al. 2009: 168 , figs 1–6.

Type material examined. Holotype female ex. C asuarina sp. ( Casuarinaceae ), AUSTRALIA: New South Wales, Avalon Beach, 26 August1934, coll. Womersley ( SAM, N1970401). Paratypes. 1 male and 1 larva, same data as holotype (1 slide; SAM, N1970400).

Non-type material examined. 10 females, 2 deutonymphs, 2 protonymphs, and 4 larvae ex. Swamp She-Oak C asuarina glauca (Casuarinaceae) , AUSTRALIA: New South Wales, Des Creagh Reserve, 35 km N of Sydney, Avalon Beach, 33º37’59” S 151º19’56” E, 24 January 2012, coll. J.J. Beard (QM, SAM, ANIC, USNM; many more in alcohol); 1 female ex. same host, AUSTRALIA: New South Wales, Dee Why, 18 km N of Sydney, Hawkesbury Avenue, 33º45’00” S 151º17’37” E, 24 January 2012, coll. J.J. Beard (QM); 4 females, 2 males, 2 deutonymphs, 1 protonymph, and 1 larva, ex. same host, AUSTRALIA: Queensland, Beachmere, Bayside Drive, 27°05’50’’S, 153°05’20’’E, 15 February 2009, coll. O.D. Seeman (QM); 3 females, 1 male, 1 protonymph, and 1 larva ex. same host, AUSTRALIA: Dutton Park State School, 27º29’38’’ S 153º01’43’’ E, 16 June 2011, coll. O.D. Seeman (QM).

Diagnosis. Prodorsal shield with fine longitudinal to oblique folds centrally, with weak reticulate pattern posterolaterally. Opisthosomal shield with fine oblique folds sublaterally; with fine longitudinal folds posterior e1- e1; with stronger transverse folds just anterior d1-d1 and between d1-e1. Lateral cuticle weakly to coarsely papillate. Dorsal cuticle finely punctate. Dorsal setae concave in shape (scoop-shaped).

FEMALE (n = 19). Dorsum. ( Figs 107 a, 108, 109, 110b, 111a) Body measurements: distance between setae v2 -h1 305–335 [320]; sc2-sc2 105–125 [115]; other measurements: v2-v 2 26–36 [32], sc1-sc1 88–100 [89], c1-c 1 15–25 [20], c3-c3 130–145 [140], d1-d 1 18–24 [21], d3-d3 115–125 [115], e1- e 1 19–28 [21], e3-e3 105–120 [107], f3-f3 83–97 [87], h1-h 1 21–34 [21], h2-h2 54–67 [54]. Gnathosoma completely concealed beneath anterior margin of prodorsum ( Figs 109 , 110 a, 111). Cuticle between gnathosoma and prodorsum produced into 1 pair of blunt, broadly triangular membranous lobes ( Figs 110 , 111 ) (with median notch formed between lobes); median notch anterior and ventral to setae v2 (notch internal depth 19–26); lobes can sometimes be retracted beneath anterior margin of prodorsum ( Figs 110 , 111 a); setae v2 inserted just ventral to, or on edge of, anterior margin of prodorsum ( Figs 107 a, 108, 110a, 111a). Prodorsum with 6–8 strong longitudinal to oblique folds running almost entire length of shield centrally; cuticle with many fine folds and finely punctate, with some fine folds and weak reticulation in posterior lateral corner. Opisthosoma finely punctate with 2 transverse to oblique folds across shield, between c1- d1 and d1-e1; cuticle laterad c1-c1 and d1-d1 finely reticulate and folded; cuticle in general with many fine oblique folds and wrinkles, becoming longitudinal posteriorly. Soft cuticle laterad shield strongly colliculate-papillate (sculpturing on Queensland material much weaker than material from type locality). All dorsal setae short, weakly spatulate, barbed; dorsal setae with distinctly concave ventral surface, forming a scoop ( Figs 107 , 113 b, 119b); setae d1 and e1 much smaller than other dorsal setae. Setal lengths: v 2 16–20 [17], sc 1 14–18 [not measurable], sc 2 15–20 [not measurable], c 1 10–16 [not measurable], c 3 15–20 [16, 18], d1 6–9 [not measurable], d 3 15–19 [17], e1 4 –8 [not measurable], e 3 15 –18 [18], f 3 15–19 [17], h 1 11–16 [not measurable], h 2 13–19 [16, 17]. Palps. ( Figs 107 b, 110a) Setal formula 0, 0, 2 (1s+1e); seta-like tarsal eupathidium 5–12 long [not measurable]; solenidion 6–9 long [not measurable]. Venter. ( Figs 110 a, 112a, 113) Cuticle between 1b -1b with transverse striae; 1b -1a with longitudinal striae; 1a -3a with transverse striae; 3a -4a with longitudinal striae; cuticle posterior to 4a with small area of transverse to mixed striae becoming longitudinal to ag and coarse around genital region; cuticle on anal plates with weak oblique striae. Genital setae inserted in more-or-less transverse row on genital flap, with g1 slightly posterior to g2. Anal setae ps1–3 short, fine, inserted along medial margin of anal plates in more-or-less longitudinal line. Coxal setae fine; setae 1a, 3a, 4a finely tapered. Setal lengths: 1a 35–62 [56], 1b 12–22 [19], 2b 11–24 [21], 2c 11–21 [21], 3a 31–61 [31], 3b 12–21 [15], 4a 21–59 [42], 4b 14–20 [16], ag 1 6–15 [15], g 1 12–20 [20], g 2 11–20 [20], ps 1 8–13 [11], ps 2 8–12 [10], ps 3 5–11 [9, 10]. Spermatheca. ( Fig. 112 b) Not visible in holotype. Spermathecal tube narrow, coiled, maximum 1 wide, ca. 75–100 long, ending in small rounded vesicle 2 long, 2 wide, subtended by small sac 1 long, 1 wide. Genital opening just anterior to setae ps3. Legs. ( Fig. 114 ) Setal formula for legs I–IV (coxae to tarsi) 1-0-3-0-3-8(1), 2-0-3-0-3-8(1), 1-1-2-0-2-4, 1-0-1-0-2-4. Tarsi I and II each with 1 antiaxial solenidion ω" (ta I 8–11 [8, 9] long, ta II 9–12 [9] long) and 2 eupathidia pζ'-pζ" (6–8 [6] long). Solenidia are of similar size to the male ( Fig. 115 ). One specimen with an aberrant setal count of 3 on 1 ge III. Leg setation as in Table 1 except: cx I without 1c; tr I–IV without v ′ (l' present on tr III); ge I–IV nude; ti I–IV without v′′; ta I–IV without tc′′.

MALE (n = 2). Dorsum. ( Figs 116, 117 , 119 a). Paratype measurements in brackets. Body measurements: distance between setae v2 -h1 220–230 [230]; sc2-sc2 80–91 [91]; other measurements: v2-v 2 22–25 [25], sc1-sc1 63–72 [72], c1-c 1 14–16 [14], c3-c3 95–98 [98], d1-d 1 10–11 [10], d3-d3 73–79 [79], e1- e 1 14–17 [17], e3- e3 70– 76 [76], f3-f3 56–63 [63], h1-h 1 11–15 [15], h2-h2 34–42 [42]. Gnathosoma completely concealed beneath anterior margin of prodorsum. Anterior margin of prodorsum with a deep medial notch forming 1 pair of blunt, broadly triangular lobes as in female, can appear to be retracted beneath anterior margin of prodorsum; setae v2 inserted just ventral to, or on edge of, anterior margin of prodorsum ( Figs 116, 117 , 119 a). Prodorsal cuticle with multiple longitudinal to oblique folds running along almost entire length of shield. Opisthosoma with mesonotal and pygidial shields, separated by a band of transversely folded soft cuticle; shields with weak reticulate and folded cuticle. Soft cuticle laterad shield strongly colliculate-papillate (sculpturing on Queensland material much weaker than material from type locality). All dorsal setae short, weakly spatulate, barbed; dorsal setae with distinctly concave ventral surface forming a scoop ( Fig. 119 b); setae d1 and e1 much smaller than other dorsal setae. Setal lengths: v 2 15–20 [18, 20], sc 1 13–15 [14, 15], sc 2 15–18 [17, 18], c 1 13–14 [13], c 3 14–15 [14, 15], d1 5–8 [6], d 3 14–15 [15], e1 5 –6 [4, 5], e 3 14 –16 [15, 16], f 3 14–15 [14, 15], h 1 12–14 [12, 13], h 2 11–15 [15]. Palps. Palps similar to female. Solenidion 8–11 [11] long, seta-like eupathidium 7–13 [13] long. Venter. ( Figs 118 a, 119b) Cuticle mostly with fine striae between 1a -4a; broadly separated transverse striae between 4a -ag; weak, broadly separated transverse striae between ag -g1–2. Genital setae inserted in more-or-less transverse row. Anal setae ps2– 3 fine, inserted in transverse row laterad ps1; ps1 modified into thick, straight, spur-like setae ( Figs 118 a, 119b). Coxal, genital and anal setae fine; setae 1a, 3a, 4a finely tapered and difficult to determine total length. Setal lengths: 1a 45–63 [50, 65], 1b 14–19 [19], 2b 11–18 [18], 2c 13–16 [16], 3a 30–53 [50, 53], 3b 8–17 [17], 4a 37– 67 [67], 4b 10–18 [18], ag 1 9–10 [9, 10], g 1 7–10 [10], g 2 8–13 [12, 13], ps 1 5–13 [13], ps 2 7–11 [7], ps3 5–8 [7, 8]. Aedeagus. ( Fig. 118 b) Narrow, sclerotised, tapering to a point, 41–42 [42] long (bent tip is possibly artefact of slide mounting). Membranous duct runs from inside aedeagus for about 55, reaching partially distinguishable membranous sac, at least 10 wide, 10 long (not visible in paratype). Legs. Setal formula for legs I–IV (coxae to tarsi) same as female: 1-0-3-0-3-8(1), 2-0-3-0-3-8(1), 1-1-2-0-2-4, 1-0-1-0-2-4. Tarsi I and II each with 1 antiaxial solenidion ω" (ta I 8–10 [10] long, ta II 8–10 [9, 10] long) and 2 eupathidia pζ'-pζ" (5–7 [7] long). Solenidia similar in size to female ( Fig. 115 ).

DEUTONYMPH (n = 4). Dorsum. Body measurements: distance between setae v2 -h1 210–245, sc2-sc2 75– 100; other measurements: v2-v 2 17–23, sc1-sc1 68–87, c1-c 1 17–21, c3-c3 87–125, d1-d 1 16–21, d3-d3 67–99, e1- e 1 19–23, e3- e3 61–97, f3-f3 53–82, h1-h 1 15–21, h2-h2 41–54. Prodorsal shield with 7–9 longitudinal creases; setae v2 inserted on anterior margin of prodorsal shield. Opisthosoma with setae c1 on paired, weak, irregular platelets, d1-d3 on paired, weak, irregular platelets; pygidial shield weak, including setae e1, f3, h1, h2. Otherwise coarse transverse striae between areas of smooth to wrinkled cuticle. At least 6 small pores present on dorsum, 2 pairs on prodorsal shield mesad sc2, pair between c1-c3, pair between d1-d3, pair anterolaterad e1, pair posterior e1. Setal lengths: v 2 15–21, sc 1 12–18, sc 2 12–17, c 1 9–11, c 3 12–17, d1 4–7, d 3 15–19, e1 2 –6, e 3 14 –19, f 3 14– 20, h 1 7–13, h 2 14–19. 1 specimen lacks setae c1, e1 and h2 on the right hand side. Palps. Palps similar to adult. Solenidion 3–5 long, seta-like eupathidium 5–8 long. Venter. Cuticle between 1b-1a with longitudinal striae; 1a to level with leg III with transverse striae; between legs III–IV with longitudinal striae; cuticle posterior to leg IV transverse becoming longitudinal and broader in genital region. Coxal setae fine. Setae ag1, g1, ps1–3 smooth. Setal lengths: 1a 22–44, 1 b 9–16, 2 b 9–13, 2 c 9–16, 3 a 26–38, 3 b 8–18, 4 a 25–34, 4 b 10–13, ag1 6–8, g 1 9–14, ps1 4–6, ps2 4–6, ps3 5–7. Legs. Setal formula for legs I–IV same as adult female. Tarsi I and II each with 1 antiaxial solenidion ω" (3–5 long) and 2 eupathidia pζ'-pζ" (4–6 long).

PROTONYMPH (n = 4). Dorsum. Body measurements: distance between setae v2 -h1 185–200, sc2-sc2 69– 77; other measurements: v2-v 2 18–20, sc1-sc1 62–67, c1-c 1 15–16, c3-c3 82–89, d1-d 1 15–16, d3-d3 66–71, e1- e 1 12–15, e3- e3 63–68, f3-f3 50–52, h1-h 1 7–14, h2-h 2 27–33. Dorsum similar to deutonymph. Prodorsal shield with 6–7 longitudinal creases; setae v2 inserted just ventral to anterior margin of prodorsal shield. Opisthosomal shields similar to deutonymph except pygidial shield excludes f3. At least 5 small pores present on dorsum, pair on prodorsal shield mesad sc2, pair between c1-c3, pair between d1-d3, pair anterolaterad e1, pair posterior e1. Setal lengths: v 2 14–20, sc 1 11–14, sc 2 14–16, c1 6–8, c 3 13–15, d1 4–5, d 3 13–15, e1 3 –5, e 3 13 –16, f 3 13–16, h 1 5– 10, h 2 13–16. Palps. Palps similar to adult. Solenidion 3 long, seta-like eupathidium 5–7 long. Venter. Cuticle and setae similar to deutonymph. Setal lengths: 1a 25–32, 1 b 10–16, 2 b 10–12, 3 a 22–31, 3 b 8–12, ag1 3–6, ps1 3–5, ps2 3–5, ps3 3–5. Legs. Setal formula for legs I–IV (coxae to tarsi) 1-0-3-0-3-8(1), 1-0-3-0-3-8(1), 1-1-2-0-2-4, 0-0- 1-0-2-3. Tarsi I and II each with 1 antiaxial solenidion ω" (3–4 long) and 2 eupathidia pζ'-pζ" (4–5 long). Leg setation as in deutonymph, except: setae 2c, 4b absent; tarsi IV without seta tc ′. Setae l' added to tr III.

LARVA (n = 8). Dorsum. ( Fig. 120 a) Body measurements: distance between setae v2 -h1 120–180 [paratype: 165], sc2-sc2 57–69 [63]; other measurements: v2-v 2 16–22 [19], sc1-sc1 51–61 [54], c1-c 1 13–17 [17], c3-c3 71– 95 [83], d1-d 1 15–18 [15], d3-d3 50–69 [61], e1- e 1 9–13 [11], e3- e3 36–60 [50], f3-f 3 27–41 [38], h1-h1 4–7 [4], h2-h 2 14–18 [17]. Anterior margin of prodorsum smoothly rounded without medial notch. Prodorsal shield smooth, weak with few oblique folds; opisthosomal dorsum with a few transverse folds and striations between c1- e1. Lateral cuticle mesad c3 with oblique folds and striations. At least 5 pairs of pores present on dorsum, pair mesad sc2, pair between c1-c3 and d1-d3, 2 pairs laterad e1. Setae h1, h2 inserted posteroventrally. Setal lengths: v 2 13–23 [19], sc 1 10–14 [12, 13], sc 2 11–16 [13], c1 4–7 [5, 6], c 3 9–15 [12], d1 3–5 [4, 5], d 3 11–18 [16, 18], e1 2 –4 [4], e 3 11 –17 [15], f 3 12–18 [16], h1 4–7 [6, 7], h 2 12–19 [17, 19]. Palps. ( Fig. 120 b) Palps 3-segmented; setalike tarsal eupathidium 3–8 [7, 8] long; solenidion 2–3 [3] long. Venter. Ventral cuticle finely striate, similar to deutonymph. Pseudanal setae ps1–3 on smooth cuticle. Coxal setae fine. Setal lengths: 1a 15–36 [36], 1b 10–18 [12], 3a 19–35 [24], ps1 2–4 [4], ps2 2–4 [4], ps3 2–4 [4]. Legs. Setal formula for legs I–III (coxae to tarsi) 1-0-3- 0-3-7(1), 0-0-3-0-3-7(1), 0-0-2-0-2-3. Tarsi I and II each with 1 antiaxial solenidion ω" (ta I 2–4 [3, 4], ta II 2–3 [2, 3]) and 2 eupathidia pζ'-pζ" (3–5 [5] long). Leg setation as in protonymph, except: setae 2b, 3b absent; tr III without l ′; ta I–III without seta tc ′.

Remarks. Individual mites are found wedged within the natural grooves present on the stems and branchlets of the host plant ( Fig. 122 ), where they feed and moult. Eggs are also laid within these grooves, lined up in a row ( Fig. 121 ). The eggs have a short stipe and thick sculptured outer coating ( Fig. 121 b).

Although Womersley (1940) stated the sex as “probably female”, the original description and illustrations of T. conicus were unquestionably based on a male. Womersley stated that there were four specimens; however, to date only three specimens have been located (on two slides, in poor condition). Even though Womersley technically never designated a holotype, the female slide is marked with the traditional red indicative of a holotype specimen, and the male slide (with larva) is marked with the traditional blue of a paratype. There is no indication of when this was done, or by whom. The female was described much later by Smiley et al. (1996) from what they stated was the holotype. The ‘type’ slides are now supplemented by new material collected on the type host plant from both the type locality and an additional locality further north along the eastern Australian coastline.

Both the original description ( Womersley 1940) and re-description (Smiley et al. 1996) were lacking several key details, due to the poor preservation of the type specimens. However, after close examination of the types, we were able to discern certain key characters, e.g. setae e1 and three pairs of pseudanal (ps) setae, in addition to details of the leg setation. We also note, with the help of the new material, that the palp is three-segmented, not two-segmented as originally described.

The Queensland specimens have some minor differences to the specimens from the type locality: the dorsal sculpturing is weaker, there are fewer lateral papillae (ca. 25 vs 50) and most ventral, genital and anal setae are shorter. There is a chance that they may represent another species, but because they came from the same host plant, and without an assessment of variation from several populations or genomic analysis, we tentatively consider them the same species. The use of low temperature scanning electron microscopy (LT-SEM) revealed that the specimens from both localities have very similar pattern of “microplate” (sensu Welbourn et al. 2003) development on the cuticle ( Fig. 123 ).

Figures

FIGURE 107. Tegopalpus conicus Womersley, adult female from type locality, a. dorsum; b. detail of palp (scale bar for palp = 25 Μm).

FIGURE 108. Tegopalpus conicus Womersley, adult female from northern population, dorsum.

FIGURE 109. Tegopalpus conicus Womersley, adult female, type locality, in habitat.

FIGURE 110. Tegopalpus conicus Womersley, adult female, type locality, anterior margin of prodorsum, a. ventral view, with detail of palps; b. dorsal and ventral view of same individual.

FIGURE 111. Tegopalpus conicus Womersley, adult female, type locality, anterior margin of prodorsum, a. dorsal aspect; b. ventral aspect.

FIGURE 112. Tegopalpus conicus Womersley, adult female, type locality, a. posterior venter; b. spermatheca.

FIGURE 113. Tegopalpus conicus Womersley, adult female, type locality, a. venter; b. detail of ventral opisthosoma, note scoop-like dorsal setae f 3, h 1 – 2.

FIGURE 114. Tegopalpus conicus Womersley, adult female, type locality, legs (right side), eupathidia (pζ ′ - pζ ′′) not labelled on leg I.

FIGURE 115. Tegopalpus conicus Womersley, type locality, tarsus I with detail of solenidion ω ", a. adult female; b. adult male.

FIGURE 117. Tegopalpus conicus Womersley, adult male from northern population, dorsum.

FIGURE 118. Tegopalpus conicus Womersley, adult male, northern population, a. posterior venter; b. aedeagus.

FIGURE 119. Tegopalpus conicus Womersley, adult male, type locality, a. in habitat; b. detail of posterior opisthosoma, note scooplike dorsal setae h 1 – 2 and thickened setae ps 1.

FIGURE 120. Tegopalpus conicus Womersley, larva, type locality, a. dorsum; b. detail of palp (scale bar for palp = 25 Μm).

FIGURE 121. Tegopalpus conicus Womersley, eggs, type locality, a. in habitat; b. detail of egg, note stipe.

FIGURE 122. Tegopaplus conicus Womersley, type locality, in habitat (F = adult female, M = adult male, N = nymph).

FIGURE 123. Tegopalpus conicus Womersley, detail of microplate formation (sensu Welbourn et al. 2003), a. adult female from type locality; b. adult female from northern locality.