Lagynochthonius xiaolinensis Hou & Gao & Zhang 2022, sp. nov.
Creators: name: Hou, Yanmeng
name: Gao, Zhizhong
name: Zhang, Feng
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Lagynochthonius
Lagynochthonius xiaolinensis

description: Lagynochthonius xiaolinensis sp. nov. (OiHIJ伪oi)
Figs 31–34
Type material. Holotype ♂ (Ps.- MHBU-HBUARA#2021-41401): China, Yunnan Province, Zhenxiong County, Linkou Township, Xiaolin Village, Dayan Cave, under a stone in twilight zone [27°34′6.40″N, 105°4′49.40″E], 1907 m a.s.l., 29 September 2021, Zegang Feng, Yanmeng Hou, Lu Zhang & Liu Fu leg.
Etymology. Named after the village of Xiaolin, near the type locality.
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 2 setae; tergites I–III each with 2 setae. Pedipalps slender, femur 8.07 times longer than broad; chela 7.00 times longer than broad; both chelal fingers with intercalary teeth and fixed chelal finger with a modified accessory tooth (td) on dorso-antiaxial face; chemosensory setae (sc) present on dorsum of chelal hand; sensilla present.
Description. Male (holotype), female unknown (Figs 31D, 32–34).
Colour (Figs 31D, 32, 33): generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.
Cephalothorax (Figs 33B, 34A): carapace 0.94 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 2 setae flanking base; with 17 setae arranged s4s: 3: 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 3–4, 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 9–11 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. 34C); intercoxal tubercle absent; without sub-oral seta.
Chelicera (Figs 33C, 34B): large, about as long as carapace, 2.31 times longer than broad; 5 setae and 2 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 10 teeth, distal one largest; movable finger with 16 retrorse contiguous small teeth; galea represented by a very slight bump on movable finger (Fig. 34B). Serrula exterior with 22 and serrula interior with 14 blades. Rallum with 8 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. 34D).
Pedipalp (Figs 33A, 34E–G): long and slender, trochanter 1.72, femur 8.07, patella 2.05, chela 7.00, hand 2.92 times longer than broad; femur 3.10 times longer than patella; movable chelal finger 1.41 times longer than hand and 0.59 times longer than chela. Setae generally long and acuminate; 1 distal lyrifissure present on patella (Fig. 34E). 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 8 trichobothria, movable chelal finger with 4 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 between est and it and distal to b; est situated distal to b (Fig. 34F). A tiny antiaxial 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 and well-spaced teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 27 macrodenticles, slightly retrorse and pointed, plus 17 intercalary microdenticles and a modified accessory tooth on dorso-antiaxial face (td, very close to dx), 45 in total; movable chelal finger with 18 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 14 intercalary microdenticles and 6 vestigial, rounded and contiguous basal teeth, 38 in total (Fig. 34F). Fixed chelal finger with sensilla af 1–2 close together, near tip; movable chelal finger with 4 sensilla: am 1–2 near tip, p 2 slightly proximad of sb, p 1 distad of p 2 and very close to chelal teeth (Fig. 34F). Chelal fingers straight in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand (Fig. 34G).
Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 2: 3: 4: 4: 4: 4: 4: 2: T2T: 0. Sternal chaetotaxy III–XII: 13: 12: 8: 7: 7: 7: 8: 7: 0: 2. Anterior genital operculum with 10 setae, genital opening slit-like, with 11–12 marginal setae on each side, 33 in total (Fig. 33D).
Legs (Fig. 34H, I): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur I, IV and patella I, IV. Femur of leg I 1.81 times longer than patella and with 1 lyrifissure at the base of femur; tarsus 2.35 times longer than tibia. Femoropatella of leg IV 3.96 times longer than deep; tibia 6.70 times longer than deep; with basal tactile setae on both tarsal segments: basitarsus 3.44 times longer than deep (TS= 0.26), telotarsus 13.17 times longer than deep and 2.55 times longer than basitarsus (TS= 0.23). Setae of leg I (trochanter to tibia) 4: 3: 16: 10: 15, setae of leg IV (trochanter to basitarsus) 1: 3: 6: 11: 9. 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). Male: body length 2.18. Pedipalps: trochanter 0.31/0.18 (1.72), femur 1.21/0.15 (8.07), patella 0.39/0.19 (2.05), chela 1.75/0.25 (7.00), hand 0.73/0.25 (2.92), movable chelal finger length 1.03. Chelicera 0.67/0.29 (2.31), movable finger length 0.35. Carapace 0.59/0.63 (0.94). Leg I: trochanter 0.18/0.15 (1.20), femur 0.67/0.09 (7.44), patella 0.37/0.07 (5.29), tibia 0.31/0.06 (5.17), tarsus 0.73/0.06 (12.17). Leg IV: trochanter 0.25/0.16 (1.56), femoropatella 0.91/0.23 (3.96), tibia 0.67/0.10 (6.70), basitarsus 0.31/0.09 (3.44), telotarsus 0.79/0.06 (13.17).
Remarks. Female unknown. Lagynochthonius xiaolinensis sp. nov. is similar to L. serratus sp. nov. in having intercalary teeth on both chelal fingers and an equal number of setae on tergites I–III, but differs by the presence of more robust chela (e.g. chela 7.00 times longer than broad vs. 8.38–8.84 times, hand 2.92 times longer than broad vs. 3.38–3.58 times; all in males), a larger body size (body length 2.18 vs. 1.95–2.07 mm in males), and the different positions of trichobothria t and it (t situated basal to it vs. distal to it).
Lagynochthonius xiaolinensis sp. nov. differs from L. bailongtanensis in the shape of the epistome (pointed and triangular vs. rounded and obtuse), the dentation on both chelal fingers (with intercalary teeth on both chelal fingers vs. without intercalary teeth), and the number of setae on tergites I–III (2 vs. 3–4).
Lagynochthonius xiaolinensis sp. nov. differs from L. laoxueyanensis by the presence of intercalary teeth on both chelal fingers, the number of setae on tergite III (2 vs. 4) and a larger body (body length 2.18 vs. 1.78 mm in the male) (Li et al. 2019; Hou et al. 2022).
Distribution and habitat. This species is only known from the type locality, Dayan Cave (Figs 1C, 31A–C), which is located about 2 km northeast of Xiaolin Village (Zhenxiong County). This limestone cave is located at the foot of a mountain and has one large and rectangle entrance (about 80 m high and 140 m wide), approximately 600 m in length, and extends horizontally. The interior space of the cave is very large and covered with gravel. The specimen was found under a stone about 300 m from the entrance (twilight zone), at low temperature and high humidity (15°C, humidity over 85%).
description: Published as part of Hou, Yanmeng, Gao, Zhizhong & Zhang, Feng, 2022, Diversity of cave-dwelling pseudoscorpions from eastern Yunnan in China, with the description of eleven new species of the genus Lagynochthonius (Pseudoscorpiones, Chthoniidae), pp. 1-65 in Zootaxa 5198 (1) on pages 43-46, DOI: 10.11646/zootaxa.5198.1.1, http://zenodo.org/record/7251602