Lagynochthonius yaowangguensis 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 yaowangguensis

description: Lagynochthonius yaowangguensis sp. nov. (ŪƗỖIJ伪oi)
Figs 42–45
Type material. Holotype ♂ (Ps.- MHBU-HBUARA#2021-27901): China, Yunnan Province, Malipo County, Tianbao Town, Laoshanyaowanggu, cave without name (Unnamed Cave 4), under stones and detritus in deep zone [23°00'38.10"N, 104°49'17.57"E], 1221 m a.s.l., 19 April 2021, Zegang Feng leg. Paratypes: 1 ♀ (Ps.-MHBU-HBUARA#2021-27902), the same data as the holotype; 1 ♀ (Ps.- MSWU-HBUARA#2021-18001), the same location as the holotype, 22 July 2021, Zegang Feng, Hongru Xu, Liu Fu & Nana Zhan leg.
Etymology. Named after the valley of Laoshanyaowanggu, 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 small, pointed, triangular; posterior margin of carapace with 2 setae; tergites I–VII each with 4 setae. Pedipalps slender, femur 10.46 (♂), 10.07–10.38 (♀) times longer than broad; chela 8.76 (♂), 8.30–8.32 (♀) 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 absent.
Description. Male (holotype), female unknown (Figs 42F, 43A, 44A–D, 45).
Colour (Figs 42F, 43A, 44A–D): generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.
Cephalothorax (Figs 44B, 45A): carapace 0.93 times longer than broad, markedly narrowed posteriorly; surface smooth, without furrows; no traces of eyes; anterior margin slightly serrate; epistome very pointed and small, triangular, with 2 setae flanking base; with 16 setae arranged 4: 4: 4: 2: 2, preocular setae missing, 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 4–5, 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. 45C); intercoxal tubercle absent; without sub-oral seta.
Chelicera (Figs 44C, 45B): large, about as long as carapace, 2.39 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 12 teeth, distal one largest; movable finger with 11 retrorse contiguous small teeth; galea completely vestigial (Fig. 45B). Serrula exterior with 25 and serrula interior with 14 blades. Rallum with 7 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. 45D).
Pedipalp (Figs 44A, 45E–G): long and slender, trochanter 1.81, femur 10.46, patella 2.82, chela 8.76, hand 3.33 times longer than broad; femur 2.83 times longer than patella; movable chelal finger 1.64 times longer than hand and 0.63 times longer than chela. Setae generally long and acuminate; 1 distal lyrifissure present on patella (Fig. 45E). Chelal palm gradually constricted towards fingers, apodeme complex of movable chelal finger sclerotized, with weak granulation dorsally at base of fixed chelal finger. 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 situated midway between b and st; b and t situated subdistally, b situated at same level as est; t situated distal to it (Fig. 45F). 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 34 macrodenticles, slightly retrorse and pointed, plus 21 intercalary microdenticles and a modified accessory tooth on dorso-antiaxial face (td, slightly distal to dx), 56 in total; movable chelal finger with 23 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 15 intercalary microdenticles and 8 vestigial, rounded and contiguous basal teeth (Fig. 45F), 46 in total. Sensilla absent. Chelal fingers slightly curved in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand (Fig. 45G).
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: 4: 5: 5: 4: T2T: 0; tergites VIII and IX each with an unpaired median seta. Sternal chaetotaxy III–XII: 11: 9: 8: 8: 7: 8: 7: 9: 0: 2. Anterior genital operculum with 9 setae, genital opening slit-like, with 14–15 marginal setae on each side, 38 in total (Fig. 44D).
Legs (Fig. 45H, I): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur I, IV and patella I, IV. Femur of leg I 2.05 times longer than patella and with 1 lyrifissure at the base of femur; tarsus 2.34 times longer than tibia. Femoropatella of leg IV 5.09 times longer than deep; tibia 7.40 times longer than deep; with basal tactile setae on both tarsal segments: basitarsus 4.00 times longer than deep (TS= 0.22), telotarsus 15.17 times longer than deep and 2.84 times longer than basitarsus (TS= 0.24). Setae of leg I (trochanter to tibia) 3: 11: 11: 15, setae of leg IV (trochanter to basitarsus) 2: 3: 6: 9: 11. Arolium slightly shorter than the claws, not divided; claws simple.
Adult females (paratypes) (Figs 42G, 43B, 44E). Mostly same as male, but a little larger; carapace 0.95–0.98 times longer than broad, gently narrowed posteriorly, one female has a pair of preocular microsetae; chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5; tergal chaetotaxy I–XII: 4: 4: 4: 4: 4: 4: 4: 4: 5: 4: T2 T: 0; sternal chaetotaxy IV–XII: 10: 8: 7: 7–8: 7–9: 8–9: 8–9: 0: 2; anterior genital operculum with 9 setae, posterior margin with 10–11 marginal setae, 19–20 in total; leg IV with a long tactile seta on both tarsal segments: basitarsus 4.29–4.75 times longer than deep (TS= 0.20–0.21), telotarsus 16.00–18.60 times longer than deep and 2.53–3.10 times longer than basitarsus (TS= 0.25–0.29).
Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Male: body length 1.63. Pedipalps: trochanter 0.29/0.16 (1.81), femur 1.36/0.13 (10.46), patella 0.48/0.17 (2.82), chela 1.84/0.21 (8.76), hand 0.70/0.21 (3.33), movable chelal finger length 1.15. Chelicera 0.67/0.28 (2.39), movable finger length 0.37. Carapace 0.55/0.59 (0.93). Leg I: trochanter 0.20/0.12 (1.67), femur 0.78/0.08 (9.75), patella 0.38/0.08 (4.75), tibia 0.35/0.07 (5.00), tarsus 0.82/0.06 (13.67). Leg IV: trochanter 0.27/0.16 (1.69), femoropatella 1.12/0.22 (5.09), tibia 0.74/0.10 (7.40), basitarsus 0.32/0.08 (4.00), telotarsus 0.91/0.06 (15.17).
Females: body length 1.81–2.20. Pedipalps: trochanter 0.31–0.35/0.17–0.19 (1.82–1.84), femur 1.35– 1.41/0.13–0.14 (10.07–10.38), patella 0.49–0.52/0.18 (2.72–2.89), chela 1.83–1.91/0.22–0.23 (8.30–8.32), hand 0.68–0.69/0.22–0.23 (2.96–3.14), movable chelal finger length 1.15–1.19. Chelicera 0.70–0.74/0.29–0.30 (2.41– 2.47), movable finger length 0.39–0.40. Carapace 0.57–0.61/0.60–0.62 (0.95–0.98). Leg I: trochanter 0.19/0.13– 0.14 (1.36–1.46), femur 0.76–0.79/0.08–0.09 (8.44–9.88), patella 0.36–0.41/0.08 (4.50–5.13), tibia 0.32–0.38/0.05– 0.07 (5.43–6.40), tarsus 0.80–0.83/0.05 (16.00–16.60). Leg IV: trochanter 0.25–0.33/0.15–0.19 (1.67–1.74), femoropatella 1.09–1.17/0.19–0.21 (5.19–6.16), tibia 0.69–0.74/0.09–0.10 (7.40–7.67), basitarsus 0.30–0.38/0.07– 0.08 (4.29–4.75), telotarsus 0.93–0.96/0.05–0.06 (16.00–18.60).
Remarks. Lagynochthonius yaowangguensis sp. nov. is similar to L. fengi sp. nov. in having intercalary teeth on both chelal fingers and a pointed and triangular epistome, but differs by the longer chela (e.g. chela length 1.84 vs. 1.53–1.54 mm, movable chelal finger length 1.15 vs. 0.88–0.91 mm; all in males) and the number of setae on tergites I–IV (4 vs. 2).
Lagynochthonius yaowangguensis sp. nov. differs from L. bailongtanensis in the shape of epistome (pointed and triangular vs. rounded and obtuse), and the pattern of dentation on the chelal fingers (with intercalary teeth on both chelal fingers vs. without intercalary teeth).
Lagynochthonius yaowangguensis sp. nov. differs from L. laoxueyanensis by the number of setae on tergites I–II (4 and 4 vs. 2 and 2, respectively), and the presence of intercalary teeth on both chelal fingers (Li et al. 2019; Hou et al. 2022).
In L. yaowangguensis sp. nov., the hand of the chela is slightly narrowed and the apodeme of the movable chelal finger is weakly sclerotized, but the presence of a modified accessory tooth (td) on the dorso-antiaxial face of fixed chelal finger (Figs 45F–G, 46L) is a typical character of the genus Lagynochthonius (Chamberlin 1962; Judson 2007) and maintained in this species. Therefore, considering all the characteristic factors, it is most appropriate to place this new species in the genus Lagynochthonius.
Distribution and habitat. This species is only known from the type locality, Unnamed Cave 4 (Figs 1K, 42A–E), which is located about 0.8 km northwest of Laoshanyaowanggu (a valley near the border between China and Vietnam). The cave was found near the top of a mountain. Several boulders were scattered around the triangular entrance (about 2 meters high and 3 meters wide). The interior space is large, and extends horizontally. The total length of the cave is unknown. All specimens were collected under stones and detritus in the deep zone (temperature around 11°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 56-61, DOI: 10.11646/zootaxa.5198.1.1, http://zenodo.org/record/7251602