Lagynochthonius xiaoensis, 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 : 51-55

publication ID	https://doi.org/ 10.11646/zootaxa.5309.1.1
publication LSID	lsid:zoobank.org:pub:C930242A-041C-4CEC-8B2F-2DB671A2395D
DOI	https://doi.org/10.5281/zenodo.8090076
persistent identifier	https://treatment.plazi.org/id/03DA1A1E-FFA8-FF92-FF05-3AC1E3C23A2E
treatment provided by	Plazi
scientific name	Lagynochthonius xiaoensis
status	sp. nov.

Treatment

Lagynochthonius xiaoensis sp. nov. (OiffiṄṁae)

Figs 40–43 View FIGURE 40 View FIGURE 41 View FIGURE 42 View FIGURE 43

Type material. Holotype ♀ (Ps.- MHBU-GZC190727-01 - 01 ): China, Guizhou Province, Suiyang County, Yangchuan Sub-district, Xinglong Village , Xiao Cave , under stones in the deep zone [27°59′57.61″N, 107°10′31.85″E], 976 m a.s.l., 27 July 2019, Zegang Feng, Zhaoyi Li & Chen Zhang leg. GoogleMaps Paratype: 1 ♀ (Ps.- MSWU-GZC190727-01 - 02 ), with the same data as the holotype GoogleMaps .

Etymology. Named after the type locality, Xiao Cave.

Diagnosis (♀). Small-sized troglomorphic species with elongated appendages; carapace without eyes or eyespots; anterior margin of carapace thin, finely denticulated, epistome obtuse and small, round; posterior margin of carapace with two setae; tergites Ⅰ–VI each with four setae. Pedipalps slender, femur 5.91–6.09 times longer than broad; chela 6.33–6.47 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. Females (holotype and paratype), male unknown ( Figs 40D View FIGURE 40 , 41–43 View FIGURE 41 View FIGURE 42 View FIGURE 43 ).

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

Cephalothorax ( Figs 42C View FIGURE 42 , 43A View FIGURE 43 ): carapace 0.93 times longer than broad, gently 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 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 more than 1/2 length of medial seta; apex of coxa Ⅰ with small, rounded anteromedial process; coxae II with 7–8 terminally indented coxal spines on each side, set as an oblique row, longer spines present in the middle of the row, becoming shorter distally and proximally and incised for about half their length ( Fig. 43C View FIGURE 43 ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 42D View FIGURE 42 , 43B View FIGURE 43 ): large, about as long as carapace, 2.15 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 12–14 teeth, distal one largest; movable finger with 11 retrorse contiguous small teeth; galea represented by a very slight bump on movable finger ( Fig. 43B View FIGURE 43 ). Serrula exterior with 15–16 blades and serrula interior with 11–12 blades. Rallum with nine 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. 43D View FIGURE 43 ).

Pedipalp ( Figs 42A–B, F View FIGURE 42 , 43E–G View FIGURE 43 ): long and slender, trochanter 1.27, femur 5.91–6.09, patella 1.92–2.08, chela 6.33–6.47, hand 2.53 times longer than broad; femur 2.68–2.83 times longer than patella; movable chelal finger 1.50–1.58 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 42F View FIGURE 42 , 43E View FIGURE 43 ). 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 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 st and b; b and t situated subdistally, t situated distal to b and between it and est; est distal to b ( Fig. 43F View FIGURE 43 ). 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 24–25 macrodenticles, slightly retrorse and pointed, plus a modified accessory tooth on retrolateral face (td, close to dx), 25–26 in total; movable chelal finger with ten macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 14–16 vestigial, rounded and contiguous basal teeth, 24–26 in total ( Fig. 43F View FIGURE 43 ). Chelal fingers straight in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs 42B View FIGURE 42 , 43G View FIGURE 43 ).

Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy Ⅰ–XII: 4: 4: 4: 4: 4: 4: 5: 5–6: 5–6: 4: T2T: 0. Sternal chaetotaxy IV–XII: 12–13: 10: 8–9: 8: 10–11: 10: 9–10: 0: 2. Anterior genital operculum with 10–11 setae, posterior margin with 13–16 marginal setae, 24–26 in total ( Fig. 42E View FIGURE 42 ).

Legs ( Fig. 43H–I View FIGURE 43 ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur IV and patella IV. Femur of leg Ⅰ 1.83–1.89 times longer than patella and with one lyrifissure at the base of femur; tarsus 2.24–2.31 times longer than tibia. Femoropatella of leg IV 2.82 times longer than deep; tibia 4.25–4.86 times longer than deep; with basal tactile setae on both tarsal segments: metatarsus 2.83–3.00 times longer than deep (TS = 0.35–0.39), tarsus 9.50 times longer than deep and 2.11–2.24 times longer than metatarsus (TS = 0.32). 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 1.25–1.47. Pedipalps: trochanter 0.14/0.11 (1.27), femur 0.65–0.67/0.11 (5.91–6.09), patella 0.23–0.25/0.12 (1.92–2.08), chela 0.95–0.97/0.15 (6.33–6.47), hand 0.38/0.15 (2.53), movable chelal finger length 0.57–0.60. Chelicera 0.43/0.20 (2.15), movable finger length 0.23. Carapace 0.40/0.43 (0.93). Leg Ⅰ: trochanter 0.11–0.12/0.10 (1.10–1.20), femur 0.33–0.34/0.06 (5.50–5.67), patella 0.18/0.05–0.06 (3.00–3.60), tibia 0.16–0.17/0.04 (4.00– 4.25), tarsus 0.37–0.38/0.04 (9.25–9.50). Leg IV: trochanter 0.16–0.17/0.11 (1.45–1.55), femoropatella 0.48/0.17 (2.82), tibia 0.34/0.07–0.08 (4.25–4.86), metatarsus 0.17–0.18/0.06 (2.83–3.00), tarsus 0.38/0.04 (9.50).

Distribution. Known only from the type locality.