Lagynochthonius tuoluoensis, Hou & Feng & Zhang, 2023

Hou, Yanmeng, Feng, Zegang & Zhang, Feng, 2023, New cave-dwelling pseudoscorpions of the genus Lagynochthonius (Pseudoscorpiones, Chthoniidae) from Guizhou in China, Zootaxa 5309 (1), pp. 1-64 : 46-50

Lagynochthonius tuoluoensis sp. nov. (ŔOEṄṁae)

Figs 36–39

Type material. Holotype ♂ (Ps.- MHBU-GZC190806-01 ): China, Guizhou Province, Shuicheng District, Duge Town, Hongguang Village , Tuoluodadong Cave , under stones in the deep zone [26°18′29.76″N, 104°41′44.11″E], 1435 m a.s.l., 6 August 2019, Zegang Feng, Zhaoyi Li & Chen Zhang leg. Paratypes: 1 ♂ (Ps.- MHBU-GZC190806- 02 ) , 6 ♀ (Ps.- MSWU-GZC190806-03 – GZC190806-08 ), all with the same data as the holotype .

Etymology. Named after the type locality, Tuoluodadong Cave.

Diagnosis (♂ ♀). Small-sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin and finely denticulated, epistome obtuse and small, round; posterior margin of the carapace with two setae; tergites Ⅰ–II each with two setae, tergites III–IV each with four setae. Pedipalps slender, femur 6.67–6.89 (♂), 6.45–6.80 (♀) times longer than broad; chela 5.87–6.21 (♂), 5.76–5.88 (♀) times longer than broad; chelal fingers without intercalary teeth but fixed chelal finger with a modified accessory tooth (td) on retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand.

Description. Males (holotype and paratype) ( Figs 37A , 38A–F , 39 ).

Colour: generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.

Cephalothorax ( Figs 38C , 39A ): carapace 1.06–1.09 times longer than broad, markedly narrowed posteriorly; surface smooth, without furrows; no traces of eyes; anterior margin slightly serrate; epistome obtuse and small, round, with two setae flanking base; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with two pairs of lyrifissures, first pair situated middle to the setae of ocular row, the second situated exterior to the sole pair of setae of posterior row. Chaetotaxy of coxae: P 3, Ⅰ 3, II 4, III 5, IV 5; manducatory process with two acuminate distal setae, anterior seta more than 1/2 length of medial seta; apex of coxa Ⅰ with small, rounded anteromedial process; coxae II with 8–10 terminally indented coxal spines on each side, set as an oblique and arc row, longer spines present in the middle of the row, becoming shorter distally and proximally and incised for about half their length ( Fig. 39C ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 38D , 39B ): large, about as long as carapace, 2.13–2.33 times longer than broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal seta shorter than others; movable finger with one medial seta. Cheliceral palm with moderate hispid granulation on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with ten teeth, distal one largest; movable finger with 8–9 retrorse contiguous small teeth; galea absent ( Fig. 39B ). Serrula exterior with 16–17 blades and serrula interior with 10–11 blades. Rallum with eight blades, the distal one longest and recumbent basally, with fine barbules and slightly set apart from the other blades, latter tightly grouped and with long pinnae, some of which are subdivided ( Fig. 39D ).

Pedipalp ( Figs 38A–B, E , 39E–G ): long and slender, trochanter 1.33–1.50, femur 6.67–6.89, patella 2.20–2.33, chela 5.87–6.21, hand 2.27–2.43 times longer than broad; femur 2.82–2.86 times longer than patella; movable chelal finger 1.56–1.59 times longer than hand and 0.60–0.62 times longer than chela. Setae generally long and acuminate; one distal lyrifissure present on patella ( Figs 38E , 39E ). Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized, with weak granulation dorsally at base of fixed chelal finger and hand. Fixed chelal finger and hand with eight trichobothria, movable chelal finger with four trichobothria, ib and isb situated close together, submedially on dorsum of chelal hand; eb, esb and ist forming a straight oblique row at base of fixed chelal finger; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, very close to chelal teeth; dx situated distal to et; sb closer to st than to b; b and t situated subdistally, t situated distal to b; it and est situated between b and t ( Fig. 39F ). A tiny retrolateral lyrifissure present at base of fixed chelal finger (situated distal to ist). Both chelal fingers with a row of teeth, homodentate, spaced regularly along the margin, larger and well-spaced teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 26–27 macrodenticles, slightly retrorse and pointed, plus a modified accessory tooth on retrolateral face (td, near tip), 27–28 in total; movable chelal finger with 11 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 16–17 vestigial, rounded and contiguous basal teeth, 27–28 in total ( Fig. 39F ). Chelal fingers slightly curved in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs 38B , 39G ).

Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy Ⅰ–XII: 2: 2: 4: 4: 4: 4: 4–6: 5–6: 5–6: 4–5: T2T: 0. Sternal chaetotaxy III–XII: 12–14: 14: 8–10: 8–9: 8–10: 8–10: 9–11: 9: 0: 2. Anterior genital operculum with 11–12 setae, genital opening slit-like, with 13–16 marginal setae on each side, 38–43 in total ( Fig. 38F ).

Legs ( Fig. 39H–I ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur IV and patella IV. Femur of leg Ⅰ 1.94–2.06 times longer than patella and with one lyrifissure at the base of femur; tarsus 2.38–2.47 times longer than tibia. Femoropatella of leg IV 2.33–2.59 times longer than deep; tibia 4.71 times longer than deep; with basal tactile setae on both tarsal segments: metatarsus 3.20 times longer than deep (TS = 0.38), tarsus 9.25–9.50 times longer than deep and 2.31–2.38 times longer than metatarsus (TS = 0.27–0.29). Arolium slightly shorter than the claws, not divided; claws simple.

Adult females (paratypes) ( Figs 36C , 37B , 38G ). Mostly same as males, but a little larger on average; with same coxal chaetotaxy as males; tergal chaetotaxy Ⅰ–XII: 2: 2: 4: 4: 5–6: 5–6: 5–6: 6–7: 6–7: 3–4: T2T: 0; sternal chaetotaxy IV–XII: 11–12: 9–11: 8–10: 9–11: 10–12: 11: 11: 0: 2; anterior genital operculum with 12 setae, posterior margin with 12–13 marginal setae, 24–25 in total; leg IV with a long tactile seta on both tarsal segments: metatarsus 3.00–3.40 times longer than deep (TS = 0.33–0.35), tarsus 10.00–10.25 times longer than deep and 2.28–2.35 times longer than metatarsus (TS = 0.24–0.28).

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.14–1.28. Pedipalps: trochanter 0.12–0.15/0.09–0.10 (1.33–1.50), femur 0.60–0.62/0.09 (6.67–6.89), patella 0.21–0.22/0.09–0.10 (2.20–2.33), chela 0.87–0.88/0.14–0.15 (5.87–6.21), hand 0.34/0.14–0.15 (2.27–2.43), movable chelal finger length 0.53–0.54. Chelicera 0.34–0.35/0.15–0.16 (2.13–2.33), movable finger length 0.18– 0.19. Carapace 0.37–0.38/0.35 (1.06–1.09). Leg Ⅰ: trochanter 0.08–0.10/0.09 (0.89–1.11), femur 0.31–0.33/0.05– 0.06 (5.50–6.20), patella 0.16/0.05 (3.20), tibia 0.15–0.16/0.04–0.05 (3.00–4.00), tarsus 0.37–0.38/0.04 (9.25– 9.50). Leg IV: trochanter 0.12–0.15/0.09–0.10 (1.20–1.67), femoropatella 0.42–0.44/0.17–0.18 (2.33–2.59), tibia 0.33/0.07 (4.71), metatarsus 0.16/0.05 (3.20), tarsus 0.37–0.38/0.04 (9.25–9.50).

Females: body length 1.44–1.64. Pedipalps: trochanter 0.13/0.10–0.11 (1.18–1.30), femur 0.68–0.71/0.10–0.11 (6.45–6.80), patella 0.24–0.25/0.12 (2.00–2.08), chela 0.94–0.98/0.16–0.17 (5.76–5.88), hand 0.38–0.40/0.16–0.17 (2.35–2.38), movable chelal finger length 0.57–0.59. Chelicera 0.39–0.41/0.17–0.19 (2.16–2.29), movable finger length 0.20–0.22. Carapace 0.40–0.43/0.40–0.43 (1.00). Leg Ⅰ: trochanter 0.11/0.08–0.10 (1.10–1.38), femur 0.35– 0.39/0.06 (5.83–6.50), patella 0.19/0.05–0.06 (3.17–3.80), tibia 0.17–0.18/0.04–0.05 (3.60–4.25), tarsus 0.40– 0.43/0.04 (10.00–10.75). Leg IV: trochanter 0.13–0.15/0.11–0.12 (1.18–1.25), femoropatella 0.47–0.50/0.18–0.19 (2.47–2.78), tibia 0.35/0.07–0.08 (4.38–5.00), metatarsus 0.17–0.18/0.05–0.06 (3.00–3.40), tarsus 0.40–0.41/0.04 (10.00–10.25).

Distribution. Known only from the type locality.

Figures

FIGURE 36. Tuoluodadong Cave, type locality of Lagynochthonius tuoluoensis sp. nov., A. Entrance; B. Area where L. tuoluoensis sp. nov. specimens were collected; C. Live female of L. tuoluoensis sp. nov. in its natural environment.

FIGURE 37. Lagynochthonius tuoluoensis sp. nov., A. Holotype male, habitus (dorsal view); B. Paratype female, habitus (dorsal view).

FIGURE 38. Lagynochthonius tuoluoensis sp. nov., holotype male (A–F), paratype female (G): A. Left chela (lateral view); B. Left chela (dorsal view); C. Carapace (dorsal view); D. Left chelicera (dorsal view); E. Left pedipalp (minus chela, dorsal view); F. Male genital area (ventral view); G. Female genital area (ventral view).

FIGURE 39. Lagynochthonius tuoluoensis sp. nov., holotype male:A. Carapace (dorsal view); B. Left chelicera (dorsal view), with details of teeth; C. Coxal spines on coxae II (ventral view); D. Rallum; E. Left pedipalp (minus chela, dorsal view); F. Left chela (lateral view), with details of teeth and trichobothrial pattern; G. Left chela (dorsal view); H. Leg Ⅰ (lateral view); I. Leg IV (lateral view). Scale bars: 0.10 mm.