Lagynochthonius guanniuensis, 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 : 11-16

Lagynochthonius guanniuensis sp. nov. (ΪϮṄṁae)

Figs 6–9

Type material. Holotype ♀ (Ps.-MHBU-GZXF-20-02-01): China, Guizhou Province, Xifeng County, Wenquan Town, Wenquan Village , Guanniu Cave , under the detritus in the deep zone [27°13'24.00″N, 106°52'18.00″E], 853 m a.s.l., 15 August 2020, Zegang Feng, Hongru Xu & Yanmeng Hou leg. Paratype: 1 ♀ (Ps.-MSWU-GZXF-20-02- 02), with the same data as the holotype .

Etymology. Named after the type locality, Guanniu Cave.

Diagnosis (♀). Moderately sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome pointed and small, triangular; posterior margin of carapace with two setae; tergites Ⅰ–IV each with two setae. Pedipalps slender, femur 8.19–8.47 times longer than broad; chela 6.86–7.03 times longer than broad; chelal fingers with intercalary teeth; chelal fingers markedly curved in dorsal view; chemosensory setae (sc) present on dorsum of chelal hand.

Description. Females (holotype and paratype), male unknown ( Figs 6D , 7–9 ).

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

Cephalothorax ( Figs 8C , 9A ): carapace 0.95–0.97 times longer than broad, gently narrowed posteriorly; surface smooth, without furrows; no traces of eyes; anterior margin slightly serrate; epistome pointed and small, triangular; 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, second pair situated lateral 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 less than 1/2 length of medial seta; apex of coxa Ⅰ with small, rounded anteromedial process; coxae II with 8–9 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. 9C ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 8D–E , 9B ): large, about as long as carapace, 2.48–2.50 times longer than broad; five setae (right chelicera with six 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 11–12 teeth, distal one largest; movable finger with 15–17 retrorse contiguous small teeth; galea absent ( Fig. 9B ). Serrula exterior with 21–23 blades and serrula interior with 13–14 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. 9D ).

Pedipalp ( Figs8A–B, G , 9E–G ):long and slender, trochanter1.23–1.33, femur 8.19–8.47,patella 2.39–2.52, chela 6.86–7.03, hand 2.57–2.62 times longer than broad; femur 2.47–2.62 times longer than patella; movable chelal finger 1.65–1.67 times longer than hand and 0.62 times longer than chela. Setae generally long and acuminate; one distal lyrifissure present on patella ( Figs 8G , 9E ). Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized, with weak granulation dorsally at base of fixed chelal finger. 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 an 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 situated midway between b and st; b and t situated subdistally, t situated at the same level as it and distal to b; est situated distal to b ( Fig. 9F ). A tiny retrolateral lyrifissure present at base of fixed chelal finger (situated distal to ist). Both chelal fingers with a row of teeth, heterodentate, spaced regularly along the margin, larger teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 33 macrodenticles, slightly retrorse and pointed, plus 25– 27 intercalary microdenticles, 58–60 in total; movable chelal finger with 29 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 25 intercalary microdenticles and 6–7 vestigial, rounded and contiguous basal teeth, 60–61 in total ( Fig. 9F ). Chelal fingers markedly curved in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs 8B , 9G ).

Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy Ⅰ–XII: 2: 2: 2: 2: 4: 4: 4: 4: 5: 2: T2T: 0, tergite IX with an unpaired median seta. Sternal chaetotaxy IV–XII: 11–14: 8–9: 7: 7: 7–8: 7: 7: 0: 2. Anterior genital operculum with 10–11 setae, posterior margin with 12–13 marginal setae, 23 in total ( Fig. 8F ).

Legs ( Fig. 9H–I ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur Ⅰ, IV and patella IV. Femur of leg Ⅰ 1.91–1.95 times longer than patella and with one lyrifissure at the base of femur; tarsus 2.50–2.54 times longer than tibia. Femoropatella of leg IV 4.32–4.76 times longer than deep; tibia 6.18–7.00 times longer than deep; with basal tactile setae on both tarsal segments: metatarsus 4.22–4.63 times longer than deep (TS = 0.26–0.27), tarsus 14.57–15.67 times longer than deep and 2.54–2.68 times longer than metatarsus (TS = 0.30–0.31). Arolium slightly shorter than the claws, not divided; claws simple.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Females: body length 2.20–2.55. Pedipalps: trochanter 0.27–0.28/0.21–0.22 (1.23–1.33), femur 1.31–1.44/0.16–0.17 (8.19– 8.47), patella 0.53–0.55/0.21–0.23 (2.39–2.52), chela 1.92–2.04/0.28–0.29 (6.86–7.03), hand 0.72–0.76/0.28–0.29 (2.57–2.62), movable chelal finger length 1.19–1.27. Chelicera 0.75–0.77/0.30–0.31 (2.48–2.50), movable finger length 0.40. Carapace 0.63–0.67/0.66–0.69 (0.95–0.97). Leg Ⅰ: trochanter 0.19–0.22/0.17 (1.12–1.29), femur 0.78–0.86/0.09–0.10 (8.60–8.67), patella 0.40–0.45/0.08–0.09 (5.00), tibia 0.32–0.35/0.06–0.07 (5.00–5.33), tarsus 0.80–0.89/0.06–0.07 (12.17–13.33). Leg IV: trochanter 0.30–0.31/0.17 (1.72–1.82), femoropatella 1.08–1.19/0.25 (4.32–4.76), tibia 0.68–0.77/0.11 (6.18–7.00), metatarsus 0.37–0.38/0.08–0.09 (4.22–4.63), tarsus 0.94–1.02/0.06– 0.07 (14.57–15.67).

Distribution. Known only from the type locality.

Figures

FIGURE 6. Guanniu Cave, type locality of Lagynochthonius guanniuensis sp. nov., A. Entrance; B. A narrow tunnel to the interior of the cave; C. Area where L. guanniuensis sp. nov. specimens were collected; D. Live female of L. guanniuensis sp. nov. in its natural environment.

FIGURE 7. Lagynochthonius guanniuensis sp. nov., holotype female, habitus (dorsal view).

FIGURE 8. Lagynochthonius guanniuensis sp. nov., holotype female:A. Left chela (lateral view); B. Left chela (dorsal view); C. Carapace (dorsal view); D. Left chelicera (dorsal view); E. Right chelicera (dorsal view); F. Female genital area (ventral view); G. Left pedipalp (minus chela, dorsal view).

FIGURE 9. Lagynochthonius guanniuensis sp. nov., holotype female: 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: 0.20 mm (A–B, E–I); 0.10 mm (C–D).