Iphidonopsis sculptus Gwiazdowicz, 2004

Makarova, Olga L., Marchenko, Irina I. & Lindquist, Evert E., 2021, Distribution, habitats, and redescription of the rare mite species Iphidonopsis sculptus Gwiazdowicz, 2004 (Mesostigmata: Ascidae), Zootaxa 4952 (3), pp. 448-464 : 452-462

Iphidonopsis sculptus Gwiazdowicz, 2004

( Figs 1–36 )

Iphidonopsis sculptus Gwiazdowicz, 2004: 155 .

Specimens examined. CANADA, ALBERTA PROVINCE: 2 females, 1 male, 2.5 mi. (4 km) SE Kananaskis Forest Experiment Station, ex bracket fungi on spruce log, 12.VIII.1970, leg. E. Lindquist; 2 females, Harvey Pass, Banff National Park, ex Dryocoetes affaber (Mann.) [ Coleoptera : Curculionidae : Scolytinae ], 12.VII.1968, leg. unspecified. RUSSIA, TVER’ REGION: 1 female, Central Forest State Reserve, spruce forest, ex Fomitopsis pinicola (Fungi: Fomitopsidaceae ), 7.VIII.2019, leg. A.V. Alexandrova; KARELIA, PETROZAVODSK REGION: 16 females, 2 males, Kivach Nature Reserve, spruce forest, ex Fomitopsis pinicola , 26.IX.2020, leg. A. Zuyev; MOSCOW REGION: 1 female, Istra City vicinity, Novorakovo vil., ex Fomitopsis pinicola on dead Betula pendula (coexistant with Zerconopsis remiger (Kramer, 1876) and Z. michaeli Evans et Hyatt, 1960 ), 17.VI.2010, leg. O. Makarova; 1 female, Moscow city, Pokrovsko-Streshnevo Park, ex Fomitopsis pinicola on Alnus glutinosa log (coexistent with Zerconopsis remiger and Z. michaeli ), 20.VII.2020, leg. O. Makarova; KOMI REPUBLIC: 4 females, 8 males, 3 deutonymphs, Pechoro-Ilychskii Nature Reserve, Yaksha vil. vicinity, mossy spruce forest, ex Trametes hirsuta (Fungi: Polyporaceae ), 27.IX.2003, leg. O. Makarova; ALTAI: 1 female, Central Altai, Seminskii Pass, 1700 m a.s.l., 51°02’ N 85°36’ E, Pinus sibiricus – Picea obovata forest, in litter, 20.VII. 2001, leg. I.I. Marchenko; 1 female, West Altai, Ust-Koksa District, Krasnaya Mt., 1900 m a.s.l., 50°05’ N 85°11’ E, alpine meadow with Pinus sibiricus , in litter, 23.VII.2017, leg. I.I. Marchenko; WEST SAYAN: 2 females, 1 male, Khakassia, 40 km from Abaza, along river Korasibo, 700 m a.s.l., 52°35’ N 90°08’ E, Abies sibirica – Picea obovata – Pinus sibiricus taiga, in litter, 25.VI.2013, leg. I.I. Marchenko; KHABAROVSKII KRAI: 1 female, Bikin District, environs of Boytsovo vil., 120 m a.s.l., 46°58′ N 134°19′ E, mixed forest with Pinus koraiensis , in litter, 5.IX.1991, leg. I.I. Volonikhina (Marchenko); PRIMORSKII KRAI: 2 females, 2 males, Ussurijskii Nature Reserve, 43°33’ N 132°16’ E, mixed forest with Pinus koraiensis , in litter, 15.VII.1988, leg. L.G. Grishina.

Redescription. Adults. Middle-sized mites with idiosoma rather pentagonal (especially pronounced in unfed mites), its anterior part triangular, lateral and posterior margins straight ( Figs 1 , 3 ). Mature adults dark-yellow or brownish in colour. Dorsal and anal/ventrianal shields strongly sclerotised and ornamented ( Figs 1–4 ). Dorsal shield covering entire dorsal and often lateral idiosoma, without lateral incisions, with lateral margins notched in males and unfed females ( Fig. 17 ) but almost smooth midlaterally in swollen females ( Fig. 7 ). Anterior and lateral areas of dorsal shield with sharp comb-like ornamentation, medial area with six pairs of deep depression with angular margins (three smaller pairs of depression on podonotal region, three larger pairs on opisthonotal region) ( Fig. 1 ). Most dorsal setae smooth, of moderate size or long, with hair-like tips ( Fig. 7 ). Five pairs of dorsal gland pores well developed (gdj 2, gdj 4, gdz 6, gdZ 3, gdZ 4); dorsal lyrifissures hardly discernible, six pairs on opisthonotal region and one pair, Rp, on soft cuticle ( Fig. 7 ).

Female. Idiosomal dorsum ( Figs 1 , 7 ). Dorsal shield length 484–612 by 292–360 width, moderately broad, length/width 1.59–1.75, its maximal width at level of setae J 1 ( Fig. 7 ). Podonotal region normally bearing 22 pairs of setae including all r -series setae (j 1–6, z 1–6, s 1–6, r 2–5). Opisthonotal region with 14 pairs of setae (S 2 always absent, R 1, R 2 on soft cuticle). Among dorsal setae, j 1 (9–13) and z 1 (8–11) shortest, awl-like, sometimes attenuated, inserted ventrally on ventrally bent anterior shield margin ( Fig. 11 ); setae s 1, s 2 (both 16–20), r 2–4 (20–28) very thin; seta J 5 (24–34) ciliated basally; caudal setae S 5 and Z 5 (44–56), directed posteromedially; other setal lengths from 26–38 (z 2, j 3) to 48–70 (S 4, Z 4); marginal setae R 1 and R 2 24–34, inserted laterally or ventrally on soft cuticle.

Idiosomal venter ( Figs 2 , 11, 12, 14, 15 ). Base of tritosternum slightly longer (20–24) than wide (13–16); laciniae 88–100 long, fused for nearly one third of entire length, with sparse long barbs along free part and short lateral spicules on fused area ( Fig. 14 ). Presternal sclerotisation undeveloped.All ventral setae smooth, needle-like. Sternal shield 90–108 length by minimal width between coxae II 66–76, consolidated with endopodal platelets between coxae I–II (shield width at this level 128–144) and between coxae II–III (shield width at this level 112–134) ( Fig. 11 ); anterior and posterior margins of shield weakly concave or straight; reticulation usually hardly visible, slightly lineate along lateral margins; shield with typical setae st 1–3 (17–20) and lyrifissures iv 1–3, vestigial gland pores gv 1 rarely visible on its posterior margin ( Fig. 12 ). Setae st 4 (16–19) on soft cuticle. Endopodal strips between coxae III and IV free. Epigynal shield length 114–136 by 66–76 wide, faintly reticulate, with lateral margins slightly widened posteriorly; seta st 5 (20–22) and paragenital poroids iv 5 off shield; anterior hyaline flap short, not extending to posterior margin of sternal shield. Epigynal shield flanked by strong subcutaneous sclerites connected with pericoxal strips behind coxa IV. Four postgenital platelets vestigial, hidden in common transverse dermal fold; one more pair of bacilliform platelets formed between setae JV 1 and ZV 1. Two pairs of bacilliform metapodal platelets present, smaller anterior platelets 11–18 x 2–5, larger posterior platelets 38–42 x 8–9. Exopodal platelets between coxae I–II and II–III small, triangular or rhomboid, hardly visible in ventral aspect; their apices encompassing opening of cutaneous glands gvb 1 and gvb 2, respectively. Anal shield expansive, generally subtrapezoidal or broadly suboval, well sclerotised, with convex anterolateral margins variably smooth or crenulate ( Figs 11, 15 ) and wide cribrum between poorly visible openings of gland pores gv 3, wider (164–168) than long (108–124), length/width 0.64–0.76, clearly pitted and slightly reticulate; paranal setae (19–22) inserted at level of posterior margin of anus, shorter than tubercle-based postanal seta (24–33), all circumanal setae needle-like; distance between anal opening and anterior shield margin 2–3 times smaller than distance between anal opening and posterior shield margin. Opisthogastric region with ten pairs of setae (JV 1–5, ZV 1–5), openings of gland pores gv 2 and four pairs of poroids; length of opisthogastric setae varying from 19–20 (ZV 1) to 30–42 (JV 5, Z V 5). Peritrematal shield rather wide, smooth, fused with ventrally bent dorsal shield margin anteriorly and exopodal platelet enveloping coxa IV posteriorly ( Fig. 11 ); lyrifissures ip 1–3 and glands gp 1–2 present. Peritreme with crenulate margins, relatively wide (268–308 x 10–14), reaching seta j 1 anteriorly. Spermathecal apparatus not visible.

Gnathosoma ( Figs 8–10 , 13, 16 , 26 ). Gnathotectum narrow (15–18), triramous; middle process apically split (3–5 partite), slightly longer (18) than side laterally dentate processes ( Fig. 9 ). Subcapitulum ( Fig. 16 ) as long (82– 85) as wide (79–84). Deutosternum of even, moderate width (14–15) ( Fig. 16 ) or broadened posteriorly up to 19–20 (as on Fig. 27 ), with seven rows of numerous denticles (9–21 denticles in each row), clearly bordered. Hypostomatic pairs hp 1 (41–44) and hp 3 (34–36) sometimes undulate, much longer than hp 2 (16–19) and pc (19–20), all setae attenuate. Corniculi rather small, 32–35 x 9–11. Internal malae somewhat longer than corniculi, sharply narrowing, with lateral margins very shortly fimbriated proximally. Buccal cavity with fimbriated paralabra well developed ( Fig. 26 ). Chelicera weak, its length without basal segment 143–159; basal segment length 54–66, with paraxial wall more elongated (as on Fig. 21b ); cheliceral digits of moderate size, ca 1.5 longer than corniculus. Fixed digit of chela with one large blunt tooth in paraxial position and thin needle-like pilus dentilis in antiaxial position; distal part of fixed digit grooved, ending in apical hook and two small opposed denticles on sides of groove margins, with circular depression between them ( Fig. 8 ); dorsal seta (16–17) lanceolate; lateral and dorsal lyrifissures narrow, hardly visible. Movable digit (37–40) bidentate, its arthrodial membrane smooth. Palp length 128–152; internal seta of trochanter (40–48) resembling hp 1 in form and length but swollen basally, much longer than external seta (14–16); palp with three typically specialised thick setae on femur and genu; femoral al and genual al -1 12–17 long, conical apically; genual al -2 much longer (20–23), flattened apically, with blunt oblique tip ( Fig. 13 ); palp tarsus with two distinctive setae—one thick truncate (20–22) and one sinuous (S-like) ( Fig. 10 ).

Legs ( Figs 28, 29 , 33, 34 ). Legs of moderate length (I 304–396, II 272–384, III 260–344, IV 332–468); leg I clearly shorter than dorsal shield. Length of tarsus I 64–94, tarsus IV 100–150. Leg chaetome as described for genus Zerconopsis ( Lindquist and Evans, 1965) ; setation of legs I, II, III, IV, genua: 12–10–8–7; tibiae: 12–9–7–7; chaetotactic formulae for genua I–II–III–IV: (2–3/2, 2/1–2) (2–3/1, 2/1–1) (1–2/1, 2/1–1) (1–2/1, 2/0–1); tibiae: (2–3/2, 2/1–2) (2–2/1, 2/1–1) (1–1/1, 2/1–1) (1–1/1, 2/1–1); seta av -2 on genu I and tibia I present; femur I with seta pl -2 moved ventrally (as on Fig. 24 ). Setae of legs smooth, spiniform or hair-like distally, generally of moderate length or short, only tarsus I distally with four long thin setae and tarsi II–IV each with dorso-proximal setae ad -2, pd -2 curved, almost as long as interval from their insertion to apex of tarsus ( Figs 33, 34 ); most dorsal and several lateral and ventral setae on femora, genua and tibiae of all legs inserted on tubercles (as on Figs 24, 25, 28, 29 ); distal verticil setae on tarsi II–IV rather small, almost evenly distant from apex; av -1, pv -1 (11–15) slightly shorter than al -1, pl -1 (13–18) (as on Fig. 36 ). Ambulacrum I on short pedicel, claws I (8–10) twice smaller than claws II–IV (14–17). Ambulacra of legs II–IV (length 24–32) with short thin paradactyli (9–14) hardly extending beyond apices of claws (as on Fig. 36 ). Tarsi II–IV with apical setae ad -1 and pd -1 small (10–15), about half as long as pretarsus to base of claws. Tarsus I with 7 rod-like solenidia (5 of them inserted apically).

Male. Idiosomal dorsum ( Fig. 3 ). Dorsal shield length 398–456 by 234–280 width, length/width 1.61–1.82. Chaetotaxy and ornamentation of dorsal shield similar to that of female but setae j 2–6, z 2, z 5, J 1–5 (18–28) much shorter than setae in series Z and S (40–50). Seta j 1 awl-like, short (8–10); z 1 very thin (6–11); length of s 1, s 2 14–15, r 2–4 16–20; posterior marginal series only with one seta, R 1 (18–20).

Idiosomal venter ( Figs 4 , 17, 18, 22, 23 ). Tritosternum slightly smaller than in female: base 14–18 long, 11–13 wide; laciniae 68–76 long, distally with long barbs. Sternitigenital shield united with endopodal platelets developed between coxae I–II and II–III ( Figs 17, 23 ); its anterior margin medially concave, tightly abutting genital valve, posterior margin convex; shield length 160–174, width before coxae II 114–120, width at midlevel of coxae II 60–66, width at level of middle angles 108–118, width at midlevel of coxae IV 44–54; glands gvb 1 and gvb 2 associated with triangular exopodal platelets between coxae I–II and II–III, respectively ( Fig. 23 ). Endocoxal angular platelets between coxae III–IV free. Sternitigenital shield with vestigial reticulate ornamentation, three pairs of lyrifissures iv 1–3, and setae st 1–3, st 5 (17–19) usually slightly longer than seta st 4 (13–17). Genital valve transverse oval (11– 13 x 24–32), inner funnel weakly narrowing ( Fig. 18 ). Leg acetabula II and III with lateral margins strengthened by row of small exopodal sclerites ( Fig. 17 ). Poroids iv 5 inserted on soft cuticle between sternitigenital and ventrianal shields. Ventrianal shield 144–160 long and 170–211 wide at level of setae ZV 1, length/width 0.75–0.91, clearly reticulated anteriorly and coarsely punctate behind setae JV 2, subtrapezoidal in form ( Fig. 17 ), with anterior margin generally convex, undulate and lateral margins often bent dorsally, consolidated with metapodal platelets ( Fig. 22 ). Ventrianal shield with 7–8 pairs of opisthogastric setae (JV 1–5, ZV 1–3; ZV 1 and nearest lyrifissure rarely on soft cuticle), three circumanal setae, two pairs of poroids and well developed openings of glands gv 3. Cribrum narrow (7–10), usually bent dorsally. Setae ZV 4 on soft cuticle.Among opisthogastric setae, ZV 1 shortest (11–17), JV 5, ZV 4 longest (up to 24–31); circumanal setae 16–20. Peritrematal shield anteriorly reduced, peritreme 248–268 x 8–11.

Gnathosoma ( Figs 5 , 19–21 , 26a, 27, 30 ). Form and size of gnathotectum (width 13–17, middle process length 16–20) similar to female; subcapitulum (70–72 x 68–76) and corniculus (23–25 x 9–10) smaller, hypostomatic seta hp 2 (14–16) and subcapitular seta pc (15–19) shorter than in female ( Fig. 30 ), length of hypostomatic seta hp 1 40–48, hp 3 35–39; internal malae in contrast to female distinctly ciliated; salivary stylus apically narrowing, 25 long ( Fig. 26a ). Deutosternum often widening posteriorly from 10–12 to 18–20 ( Figs 27, 30 ). Chelicera length without basal segment 116–128; basal segment length 52–62; fixed digit of chela with one large tooth and small denticle in paraxial position and thin needle-like pilus dentilis in antiaxial position; distal part of fixed digit grooved ( Fig. 21a ); movable digit 32–38 long, with one tooth and long tube-like spermatodactyl protruding far beyond tip of digit (length of free part 50–58) and directed downward ( Figs 5 , 21 , 30 ). Palp (112–118 long) shorter than in female; trochanter internal seta 36–44 in length, trochanter external seta 11–13, genual al -1 and femoral al 12–13, genual al -2 18–21, tarsal apical macroseta 19–21.

Legs ( Figs 24, 25 , 36 ). Length of legs I–IV: 276–292 (much shorter than idiosoma), 240–268, 236–256, and 298–324, respectively; length of tarsus I 64–75, tarsus IV 96–158. Chaetotaxy as in female including ventral position of seta pl -2 on femur I ( Fig. 24 ). Legs without dimorphically modified setae. All ambulacral structures as in female but smaller (ambulacra II–IV 21–24, their paradactyli 8–11, claws 11–14; claw I 8–10). On tarsi II–IV, length of apical setae ad -1 and pd -1 10–12; among subapical setae, av -1, pv -1 (9–11) slightly shorter than al -1, pl -1 (13–14) ( Fig. 36 ).

New description. Deutonymph. Idiosomal dorsum ( Figs 6 , 31 ). Dorsal shield 392–408 x 228–332, with lateral incisions behind setae s 6, ornamentation similar to that of female ( Figs 6 , 31 ), with prominent openings of glands gdz 6, gdZ 3, gdZ 4; podonotal region with 18 pairs of setae, opisthonotal region with 14 pairs of setae; setae j 1 (9–11) and z 1 (6–9) shortest, setae j 5, j 6, z 5, z 6, J 1–5 14–22 long, other setae longer, up to 42–48 (Z 3–5, S 3–5). Setae s 1, s 2, r 2–5 (14–19) and R 1, R 2 (17–20) inserted on soft cuticle.

Idiosomal venter ( Figs 37, 38 ). Tritosternum base 18–20 x 11–12; laciniae 74 long, with sparse long barbs in free part and shorter barbs (not spicules as in adults) in fused area ( Fig. 37 ). Sternal shield narrow, with acuminate posterior margin, weakly sclerotised ( Fig. 38 ), 188–192 long, its width at midlevel of coxae II 44, width at level of middle angles 88–100; shield bearing setae st 1–3 (18–19), st 4 (13–14) and lyrifissures iv 1–3. Setae st 5 (17), paragenital poroids iv 5 and sometimes asymmetrically poroids iv 3 on soft cuticle. Exopodal platelets not developed, openings of glands gvb 1 on soft cuticle, gvb 2 not visible. Anal shield transversely oval (60–64 x 114–118), well formed, coarsely punctate, with narrow (8) cribrum and circumanal setae 17–22 long. Opisthogastric region with 10 pairs of setae (JV 1–5, ZV 1–5) and three pairs of lyrifissures; seta ZV 1 (10–15) shortest, JV 5 (22–25) longest; metapodal platelets narrow (21–29 x 6–7); a pair of transversal bacilliform platelets developed between setae JV 1 and ZV 1 ( Fig. 38 ). Peritrematal shield reduced, peritreme long and narrow (232–264 x 6), almost extending to seta z 1, with smooth margins ( Fig. 31 ).

Gnathosoma ( Figs 32, 35 ). Gnathosomal structures in general as in adults. Tectum 14–16 wide with middle process 14–17 long ( Fig. 32 ). Subcapitulum 70–76 x 64–66; deutosternum widening posteriorly from 12 to 16; hp 1 36–40, hp 2 14–17, hp 3 30–36, pc 17–20; corniculus 20–22 x 10–11; chelicera without basal segment 120–136 long, similar to female ( Fig. 35 ); basal segment length 16–18; movable digit 28–34, chelaseta 8 long. Palp 108–114 long, trochanter with internal seta 26–32 and external seta 10–11; genual al -1 and femoral al 11–12, genual al -2 16–17, tarsal apical macroseta 17–18.

Legs. Length of legs I–IV 264–280, 256–276, 236–252, 288–312, respectively; length of tarsus I 62–68, tarsus IV 94–100. Chaetotaxy as in adults; on tarsi II–IV apical setae (d -1) 9 long, subapical (v -1) 10–11 shorter than (l -1) 13–15, dorso-proximal setae (d -2) curved, long as in adults; legs II–IV with ambulacra 20–22, paradactyli 7–10, claws 13–14 long; claw of leg I small (8–9).

Variability. The species is rather stable morphologically; the dorsal ornamentation and gnathotectum structure are especially constant. Variability concerns mainly the form of anal ( Figs 11, 15 ) and ventrianal ( Figs 17, 22 ) shields, level of reticulation of sternal/sternitigenital shield (sometimes reticulation is full but hardly visible), length of seta JV 5, and width of deutosternum and denticulation of its rows ( Figs 27, 30 ). Among females, vestigial gland gv 1 may be present or not ( Figs 11, 12 ), setae st 5 are rarely symmetrically or asymmetrically on the epigynal shield margins, minimal and maximal lengths of all legs vary 1.3–1.4 times, and those of tarsi I and IV vary up to 1.5–1.6 times. The only two females from Banff National Park, Alberta ( Canada) have six setae in Z series symmetrically, with the additional Zx seta located between Z 1 and Z 2 ( Fig. 7a ). This additional pair could be interpreted as an atavistic presence of setae S 2, whose general absence is regarded as an apomorphy of the subfamily Arctoseiinae ( Lindquist & Evans, 1965) . Whether this setal pair is an addition at the protonymphal instar, typical of S 2 ontogeny, would be a test.

Remarks. In the first description of Iphidonopsis sculptus ( Gwiazdowicz, 2004) some inaccuracies are evident. Thus, adults of this species possess 36 pairs of setae ( Fig. 7 ) on the dorsal shield (not 35 pairs, s 3 was overlooked); the dorsal shield is not really extended down onto the ventral surface (p. 154–156 in Gwiazdowicz, 2004), only onto the lateral areas; in the female, the tritosternum ( Fig. 14 ) is of different structure (not as on Fig. 3 , p. 154); in adults, the gnathotectum ( Figs 9 , 19, 20 ) has the middle projection usually longer than lateral the ones (not of the same length), and split (not obtuse) apically; in the male, dorsal marginal seta R 1 is present on soft cuticle.

Distribution. A Holarctic species. All records of Iphidonopsis sculptus are within the Temperate Zone of the Northern Hemisphere, in natural biomes of taiga and mixed forests ( Fig. 39 ).

Ecology. Found in different bracket fungi ( Fomitopsis pinicola , Trametes hirsuta ), under bark of dead spruce, in mixed or coniferous forest litter, and once on the Nearctic bark beetle, Dryocoetes affaber (Mann.) ( Coleoptera : Curculionidae : Scolytinae ).

Figures

FIGURE 39. World distribution records of Iphidonopsis sculptus Gwiazdowicz, 2004 (Gwiazdowicz, 2004; Huhta, 2016; new data).

FIGURES 1–2. Iphidonopsis sculptus Gwiazdowicz, 2004, female, micrograph habitus images. 1. Idiosomal dorsum; 2. Idiosomal venter.

FIGURES 3–6. Iphidonopsis sculptus Gwiazdowicz, 2004, micrograph images. 3. Male, idiosomal dorsum; 4. Male, idiosomal venter; 5. Male, gnathosoma ventrally; note elongated spermatodactyls; 6. Deutonymph, idiosomal dorsum.

FIGURES 7–10. Iphidonopsis sculptus Gwiazdowicz, 2004, female. 7. Idiosomal dorsum, 7a—chaetome variation; 8. Cheliceral digits; 9. Gnathotectum; 10. Palp tibia and tarsus (complete setation not shown).

FIGURES 11–16. Iphidonopsis sculptus Gwiazdowicz, 2004, female. 11. Idiosomal venter; 12. Posterior area of sternal shield, variant of structure; 13. Palp trochanter, femur, genu; 14. Tritosternum; 15. Anal shield, variant of form; 16. Subcapitulum.

FIGURES 17–23. Iphidonopsis sculptus Gwiazdowicz, 2004, male. 17. Idiosomal venter; 18. Genital valve; 19, 20. Gnathotectum; 21. Chelicera, a, b—different aspects; 22. Ventrianal shield; 23. Sternitigenital region.

FIGURES 24–30. Iphidonopsis sculptus Gwiazdowicz, 2004. 24, 25, 26a, 27, 30. Male; 26, 28, 29. Female. 24. Femur, genu and tibia I ventrally; 25. Femur, genu and tibia I dorsally; 26. Salivary stylus and paralabrum, isolated; 26a. Salivary stylus; 27. Deutosternum, variant of form; 28. Femur, genu and tibia II dorsally; 29. Femur, genu and tibia IV dorsally; 30. Gnathosoma ventrally.

FIGURES 31–38. Iphidonopsis sculptus Gwiazdowicz, 2004. 31, 32, 35, 37, 38. Deutonymph; 33, 34. Female; 36. Male. 31. Idiosomal dorsum; 32. Gnathotectum; 33. Tarsus II; 34. Tarsus IV; 35. Chelicera; 36. Ambulacrum and apex of tarsus II; 37. Tritosternum; 38. Idiosomal venter.