Pseudoblothrus arcanus, Gordana & Ambros, 2020

Turbanov, I. S. & Kolesnikov, V. B., 2020, Two new cave-dwelling species of the false scorpion genus Pseudoblothrus Beier, 1931 (Arachnida: Pseudoscorpiones: Syarinidae) from the Crimean Peninsula, Arthropoda Selecta 29 (1), pp. 28-50 : 41-47

Pseudoblothrus arcanus sp.n.

Figs 3B , 8–11 .

Obisium abeillei (E. Simon) : Lebedev, 1914: 7; Turbanov, Kolesnikov, 2015: 83; Turbanov et al., 2016: 1286.

Ideoblothrus roszkovskii Redikorzev : Pliginsky, 1927: 172; Turbanov, Kolesnikov, 2015: 83; Turbanov et al., 2016: 1286.

Syarinidae Chamberlin : Turbanov, Kolesnikov, 2015: 83; Turbanov et al., 2016: 1286.

HOLOTYPE 1 ♀ ( ZMUM TI-58 ), Crimea , Ai-Petri Karst Massif , Baydarskaya Valley , near Rodnikovskoe Village, Skelskaya Cave, 3.3.2015, leg. I.S. Turbanov.

PARATYPES: 1 ♂ ( ZMUM TI-59 ), Crimea , Ai-Petri Karst Massif , Baydarskaya Valley , near Rodnikovskoe Village, Skelskaya Cave, 25.9.2018, leg. I.S. Turbanov ; 1 ♀ ( ZISP 1436 ), 1 tritonymph ( ZMUM TI-60 ), Crimea , Ai-Petri Karst Massif , Karadagh Forest Area , Kuznetsova (= Koryta) Cave, 8.3.2014, leg. I.S. Turbanov ; 1 ♀ ( ISEA Ps. 001.0022), Crimea , Ai-Petri Karst Massif , Karadagh Forest Area , Kristalnaya (= Maksimovitcha) Cave, 3.5.2015, leg. I.S. Turbanov.

DISTRIBUTION. Known from the type locality so far.

NAME. From the Latin arcanum, which means secret, or mysterious.

DIAGNOSIS (ADULTS). A subterranean Pseudoblothrus from the Crimean Peninsula that differs from other species of the genus in the following combination of characters: four eye spots (without tapeta); carapace with 6 (rarely 5–7) setae in anterior row and 4 in posterior row; sternites III and IV with 4 stigmatal setae on each side, respectively; pedipalp smooth (hand and base of fingers with uniform, rounded granulation; base of hand and chelal pedicel reticulated); chela long, hand expanded at base and gradually narrowing distally, with nonparallel edges in dorsal views — paraxial edge of visibly convex; ist placed close to est; length of pedipalpal femur, 1.25–1.26 mm (6.25–6.30 times as long as broad), of patella, 1.0– 1.05 mm (4.34– 4.56×), of chela with pedicel, 2.0– 2.02 mm (5.26–5.77×); fixed and movable chelal fingers with 94–96 and 89–94 teeth, respectively.

DESCRIPTION OF ADULTS (♂ ♀). Troglomorphic habitus ( Fig. 3B ). Carapace, pedipalps and tergites I–II reddish brown, tergites II–XI pale brown. Opisthosoma and legs pale.

Carapace ( Figs 8A, B , 10D ) longer than broad ( Table 4 ), with two transverse furrows, with four eye spots (the front is twice as large as the rear), without tapeta. Eye spots may not be clear. Anterior margin without epistome, slightly curved forward, base of cheliceral tectum (λ) bent at an obtuse angle. Tegument covered with a weak meshwork of elongated rectangular cells. Setae thin, arranged in five main rows, chaetotaxy 5 (6–7 — ♀ paratype):4:4:4:4 (total ♀ — 21–23). The ♂ has an additional pair of bristles between the fourth and fifth row (total ♂ — 24). Three pairs of lyrifissures: two pairs between rows 1 and 2 and one pair between rows 4 and 5, respectively. Numerous minute pores all over carapace.

Coxae ( Fig. 8D ). Manducatory process triangular and acuminate, with two setae. Pedipalpal coxa covered with a fine mesh sculpturing, with several tiny pores, 8 (8–9 — ♂ ♀ paratype) setae (those of manducatory process setae not included). Leg coxae smooth, setae I: 5 (6–7 — ♂ ♀ paratype); II: 6 (7 — ♀ paratype, 8–9 — ♂ paratype); III: 4– 6 (4–5 — ♂ ♀ paratype); IV: 9 (8–9 — ♂ ♀ paratype).

Opisthosoma ( Figs 8E , 10E ). Pleural membrane longitudinally striate ( Fig. 8E ). Tergites undivided, smooth. Chaetotaxy of tergites I–XI: 4:6:6:7 (6 — ♂ ♀ paratype):9 (9 — ♀ paratype, 7 — ♂ paratype):9 (9–10 — ♂ ♀ paratype):9 (9–10 — ♂ ♀ paratype):9:9:7 (7–8 — ♂ ♀ paratype):4 (5 — ♀ paratype, 6 — ♂ paratype).

Chaetotaxy of ♀ sternites. II–XI: 13 (8–13 — paratype):15 (15–16 — paratype) + 4 suprastigmal setae on each side:9 (9–10 — paratype) + 4 suprastigmal setae on each side:12 (12–14 — paratype):13 (13–16 — paratype) + 2 (1–2 — paratype) discal setae:15 (15–16 — paratype):14 (14–16 — paratype):13 (14–15 — paratype):12 (12–14 — paratype):6 (4 — paratype).

Chaetotaxy of ♂ sternites. II with 6 discal setae; 11 of which along anterior margin of genital opening ( Fig. 10E ). III with 8 anterior setae; 4 discal setae; 13 posterior setae; 4 suprastigmal setae on each side. IV with 11 posterior setae; 6 discal setae; 4 suprastigmal setae on each side. V with 14 posterior setae; 12 discal setae. VI with 18 posterior setae; 11 glandular area setae; VII–XI with 17:16:16:14:8 setae. Ventral gland of ♂ with 2 glandular areas ( Fig. 10E ). The diameter of the ventral gland — 0.14 mm.

Anal cone with two ventral and two dorsal setae.

Genitalia. ♀ genitalia as in Fig. 8F . ♂ genitalia as in Fig. 10F , genital chamber with two unmodified setae; median genital sac with two branches.

Chelicera ( Fig. 8C ). Hand with five setae. Galeal seta (gs) 0.69 (0.66–0.69 – ♂ ♀ paratype) from base of movable finger. Galea absent in both sexes. Fixed finger with 7 (7–10 — ♂ ♀ paratype) large and 2 (3–5 — ♂ ♀ paratype) small teeth. Movable finger with 5 (5–7 — ♂ ♀ paratype) primary teeth, of which 3 (3–4 — ♂ ♀ paratype) larger than others, and 0 (0–4 — ♂ ♀ paratype) small teeth. Lyrifissures located at base of setae is and es. Rallum with 7 blades, each 0.14–0.16 mm long and finely serrate on anterior edge. Serrula exterior with 28 (27–28 — ♂ ♀ paratype) blades, serrula interior with 20 (18–19 — ♂ ♀ paratype). Hand and base of fingers reticulate-granulate. Measurements of chelicera as in Table 4 .

Pedipalp ( Figs 9 , 10A–C ). Trochanter weak reticulated; femur, patella and fingers (except of base) smooth; hand and base of fingers with uniform, rounded granulation; base of hand and chelal pedicel reticulated. Femur long, gradually broadening distally. Patella clavate, slightly expanded on mesal side at 0.3 of length from base, where five lyrifissures of different sizes are located, two of them close together. Chela long, hand expanded at base and gradually narrowing distally, with nonparallel edges in dorsal views — paraxial edge of visibly convex. Fingers slightly curved when viewed from above. Altogether, 12 trichobothria (the ♀ from Koryta Ñave absent ist – teratology ( Fig. 9E )): fixed finger with 4 in distal part of fixed finger (et, it, ist and est), 2 in basal part of fixed finger (esb and isb), and 2 on distal part of hand (ib and eb); ist placed close to est (distance ist -est slightly variable ( Figs 9B, D , 10B ); movable finger with 4 trichobothria (t, st, sb and b). Trichobothriotaxy as in Figs 9A–E , 10A, B . Hairs of trichobothria long, simple and filiform, trichobothrium t not lanceolate. Dorsal surface of chela, between finger and ib, with 1–3 irregular rows of microsetae (chemosensory setae, sc), ectal in position. Microsetae also observed over most of both fingers, adjacent to dental margin. Coupled sensilla (pc) present on movable finger between st and sb, near dental margin. Movable finger at the distal end with two apical sensilla (am 1 and am 2), fixed finger — one apical sensilla (af). Lyrifissures arranged at base of hand on dorsal side, between levels of b and esb (1 lyrifissure), between esb and isb (1 lyrifissure (in some cases this lyrifissure can be located between isb and ist, but it is observed only on one chela ( Fig. 9A )), between b and sb (2 lyrifissures), between sb and st (1 lyrifissure) and between levels of est and it on dorsal side (1 lyrifissure). Fixed finger with 94–96 small, almost pointed, contiguous teeth. Teeth of fixed finger reaching to level of isb. Movable finger with similar teeth, 89–94 in number. Teeth of movable finger not reaching as far basally as those of fixed finger (difference equivalent to about 3–4 teeth). A row of four very small denticles at base of fixed finger. Fixed finger with a welldeveloped venedens and venom gland. Lamina defensor (ld) appressed to venedens. Venom duct short, nodus ramosus well distad of et. Movable finger without venom apparatus, apodens short, with a small lamina defensor.

Legs I and IV ( Fig. 8G, H ). Surface weakly reticulate. Joint between femur and patella of leg IV perpendicular. Telotarsi not expanded, gradually tapering distally. Subterminal tarsal setae of all legs serrate distally, each with 2–3 barbs ( Fig. 8I, J ). Claws smooth, thin, arcuate, can carry one tooth (variability); arolia undivided and distinctly shorter than claws.

Measurements and ratios of adults as in Tables 4 , 5 .

DESCRIPTION OF TRITONYMPH. Carapace, pedipalps, pedipalpal coxae and chelicerae pale reddish brown, other parts pale yellow.

Carapace ( Fig. 11A ) longer than broad ( Table 4 ), with two transverse furrows, with two eye spots (without tapeta). Anterior margin without epistome, slightly curved forward, base of cheliceral tectum (λ) bent at an obtuse angle. Tegument covered with a weak meshwork of elongated rectangular cells. Setae thin, arranged in five main rows, chaetotaxy 6:4:4:4:4 (total 22). Three pairs of lyrifissures: two pairs between rows 1 and 2 and one pair between rows 4 and 5, respectively. Numerous minute pores all over carapace.

Coxae. Manducatory process triangular, acuminate, with two setae. Pedipalpal coxa covered with a fine mesh sculpturing; chaetotaxy: 7 (those of manducatory process setae not included). Surface of coxae I–IV smooth; chaetotaxy: 5– 6:6:3–4:5–6.

Opisthosoma. Pleural membrane longitudinally striate. Tergites undivided, smooth. Chaetotaxy of tergites I– XI:4:5:6:6:7:9:10:9:9:7:5. Chaetotaxy of sternites II–XI: 3:8 (+ 3 suprastigmal setae on each side):9 (+ 3 suprastigmal setae on each side):11:13 (+ 2 discal setae):15:15:14:12:6. Anal cone with two ventral and two dorsal setae.

Chelicera ( Fig. 11B ). Hand with five setae. Galeal seta (gs) 0.64 from base of movable finger. Galea absent in both sexes. Fixed finger with 12 large and 3 small teeth. Movable finger with 7 primary teeth, of which 3 larger than others, and 4 small teeth. Lyrifissures located at base of setae is and es. Rallum with 6 blades, each 0.12–0.14 mm long and finely serrate on anterior edge. Serrula exterior with 22 blades, serrula interior with 12. Hand and base of fingers reticulate-granulate. Measurements of chelicera as in Table 4 .

Pedipalp ( Fig. 11C–E ). Trochanter weak reticulated; femur, patella and fingers (except of base) smooth; hand and base of fingers with uniform, rounded granulation; base of hand and chelal pedicel reticulated. Femur long, gradually broadening distally. Patella clavate, slightly expanded on mesal side at 0.3 of length from base, where four lyrifissures of different sizes are located, two of them close together. Chela long, hand expanded at base and gradually narrowing distally, with nonparallel edges in dorsal views — paraxial edge of visibly convex. Fingers slightly curved when viewed from above. Ten trichobothria: fixed finger with 4 (et, it, ist and est) in distal part, 1 (esb) in basal part of fixed finger, 2 (ib and eb) in distal part of hand, trichobothrium isb absent; ist placed close to est; movable finger with 3 trichobothria (t, st, and b), sb absent. Trichobothriotaxy as in Fig. 11D, E . Hairs of trichobothria long, filiform, t not lanceolate. Setae of chela thin. Dorsal surface of chela with 1–2 irregular rows of microsetae (chemosensory setae, sc), ectal in position between ib and base of fixed finger. Microsetae also observed almost all over both fingers, adjacent to dental margin. Coupled sensilla (pc) present on movable finger between st and b, near dental margin. Movable finger at the distal end with two apical sensilla (am 1 and am 2), fixed finger — one apical sensilla (af). Lyrifissures arranged at base of hand on dorsal side, between b and esb (1 lyrifissure), proximal to esb (1 lyrifissure), between b and st (2 lyrifissures), and between est and it on dorsal side (1 lyrifissure). Fixed finger with 74 small, contiguous teeth. Teeth of fixed finger reaching to level of esb. Movable finger with 76 small, contiguous teeth. Teeth of movable finger extending almost as far basally as those of fixed finger (difference equivalent to about one teeth). A row of four very small denticles at base of fixed finger. Fixed finger with welldeveloped venedens and venom gland, venom duct short, nodus ramosus clearly distal to et. Lamina defensor (ld) tightly appressed to venedens. Movable finger without venom apparatus, with a short, blunt apodens and a small lamina defensor.

Legs I and IV. Surface weakly reticulate. Joint between femur and patella of leg IV perpendicular. Telotarsi not expanded, gradually tapering distally. Subterminal tarsal setae of all legs serrate distally, each with 2–3 barbs. Claws smooth, thin, arcuate, can carry one tooth (variability); arolia undivided and distinctly shorter than claws.

Measurements and ratios of tritonymph as in Tables 4 , 5 .

Protonymph and deutonymph unknown.

REMARKS. P. arcanus sp.n. is morphologically very similar to P. golovatchi sp.n., but has four eye spots (the front are twice as large as the rear) without tapeta. P. arcanus sp.n. is distinguished from P. roszkovskii by the shape of the chelal hand, which is expanded at the base and gradually narrowed distally, with nonparallel edges in dorsal view, by the paraxial edge visibly convex (in P. roszkovskii the hand has subparallel edges), and by a smaller body and a smaller number of teeth on the chela. Recognition of the new species is based on the results of molecular genetic studies (see Phylogenetic analysis of the genus Pseudoblothrus from Crimean caves above).

Figures

Fig. 3. Live specimens of two new species of the genus Pseudoblothrus in the Crimean Mountains in their natural habitat (caves): Skelskaya Cave (A) and live ♂ P. arcanus sp.n. (B) from the same cave; Villyaburunskaya Cave (C) and live ♂ P. golovatchi sp.n. (D) from the same cave. Photos by I.S. Turbanov. Рис. 3. Живые ЭкЗемплЯры двух новых видов рода Pseudoblothrus обитаюЩих в Горном Крыму в их естественной среде обитаниЯ (пеЩеры): пеЩера СкельскаЯ (A) и ♂ P. arcanus sp.n. (B) иЗ той же пеЩеры; пеЩера ВиллЯбурунскаЯ (С) и ♂ P. golovatchi sp.n. (D) иЗ той же пеЩеры. Фото И.С. Турбанова.

Fig. 8. Pseudoblothrus arcanus sp.n. Holotype (♀) from Skelskaya Cave and paratype (♀) from Kuznetsova Cave. A — carapace, dorsal view (♀ paratype). B — carapace, dorsal view (♀ holotype). C — right chelicera (♀ holotype). D — coxae of pedipalp and legs I–IV, ventral view (♀ holotype). E — sternites II–VI, ventral view (♀ holotype). F — ♀ genitalia, ventral view (♀ holotype). G — right leg I (♀ holotype). H — right leg IV (♀ holotype). I — subdistal seta of leg I (♀ holotype). J — subdistal seta of leg IV (♀ holotype). Рис. 8. Pseudoblothrus arcanus sp.n. Голотип (♀) иЗ пеЩеры СкельскаЯ и паратип (♀) иЗ пеЩеры КуЗнецова. А — карапакс, дорсально (♀ паратип). В — карапакс, дорсально (♀ голотип). С — праваЯ хелицера (♀ голотип). D — таЗики педипальп и ног I–IV, вентрально (♀ голотип). Е — стерниты II–VI, вентрально (♀ голотип). F — гениталии, вентрально (♀ голотип). G — праваЯ нога I (♀ голотип). H — праваЯ нога IV (♀ голотип). I — субдистальнаЯ Щетинка ноги I (♀ голотип). J — субдистальнаЯ Щетинка ноги IV (♀ голотип).

Fig. 9. Pseudoblothrus arcanus sp.n. Holotype (♀) from Skelskaya Cave and paratypes (♀) from Kristalnaya and Kuznetsova caves. A — right chela, ectal view (♀ holotype). B — left chela, dorsal view (♀ holotype). C — left pedipalp, minus chela, (♀ holotype). D — left chela, dorsal view, setae not illustrated (♀ paratype from Kristalnaya Cave). E — left chela, dorsal view, setae not illustrated (♀ paratype from Kuznetsova Cave). Рис. 9. Pseudoblothrus arcanus sp.n. Голотип (♀) иЗ пеЩеры СкельскаЯ и паратипы (♀) иЗ пеЩер КристальнаЯ и КуЗнецова. А — праваЯ хела, Эктально (♀ голотип), В — леваЯ хела, дорсально (♀ голотип). С — леваЯ педипальпа, беЗ хелы (♀ голотип). D — леваЯ хела, дорсально, Щетинки не покаЗаны (♀ паратип иЗ пеЩеры КристальнаЯ). Е — леваЯ хела, дорсально, Щетинки не покаЗаны (♀ паратип иЗ пеЩеры КуЗнецова).

Fig. 10. Pseudoblothrus arcanus sp.n. Paratype (♂) from Skelskaya Cave. A — left chela, ectal view. B — left chela, dorsal view. C — left pedipalp, minus chela. D — anterolateral portion of carapace. E — sternites II–VI, ventral view. F — ♂ genitalia, ventral view. Рис. 10. Pseudoblothrus arcanus sp.n. Паратип (♂) иЗ пеЩеры СкельскаЯ. А — леваЯ хела, Эктально. В — леваЯ хела, дорсально. С — леваЯ педипальпа, беЗ хелы. D — переднелатеральнаЯ часть карапакса. Е — стерниты II–VI, вентрально. F — гениталии, вентрально.

Fig. 11. Pseudoblothrus arcanus sp.n. Tritonymph from Kuznetsova Cave. A — carapace, dorsal view. B — right chelicera with serrula exterior and serrula interior. C — left pedipalp, minus chela. D — left chela, dorsal view. E — left chela, ectal view. Рис. 11. Pseudoblothrus arcanus sp.n. Тритонимфа иЗ пеЩеры КуЗнецова. А — карапакс, дорсально. В — праваЯ хелицера с внеШней и внутренней серрулами. С — леваЯ педипальпа, беЗ хелы. D — леваЯ хела, сверху. Е — леваЯ хела, Эктально.