Lagynochthonius fengi, Hou & Gao & Zhang, 2022

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), Zootaxa 5198 (1), pp. 1-65 : 11-16

publication ID	https://doi.org/ 10.11646/zootaxa.5198.1.1
publication LSID	lsid:zoobank.org:pub:019FE488-4263-4BC2-8606-446E599E226A
DOI	https://doi.org/10.5281/zenodo.7255275
persistent identifier	https://treatment.plazi.org/id/D8132CE7-D73E-420A-8CCD-15C085615416
taxon LSID	lsid:zoobank.org:act:D8132CE7-D73E-420A-8CCD-15C085615416
treatment provided by	Plazi
scientific name	Lagynochthonius fengi
status	sp. nov.

Treatment

Lagynochthonius fengi sp. nov. (Ã氏IJ伪oi)

Figs 6–9 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9

Type material. Holotype ♂ (Ps.- MHBU-HBUARA#2021-41701 ): China, Yunnan Province, Yanjin County, Miaoba Town, Maliu Village , cave without name ( Unnamed Cave 2), under the stones in deep zone [27°54′50.72″N, 104°23′29.72″E], 594 m a.s.l., 30 September 2021, Zegang Feng, Yanmeng Hou, Lu Zhang & Liu Fu leg. GoogleMaps Paratypes: 3 ♂ (Ps.- MHBU-HBUARA#2021-41702 -HBUARA#2021-41704) , 9 ♀ (Ps.- MSWU-HBUARA#2021-41705 - HBUARA#2021-41713), all with the same data as the holotype GoogleMaps .

Etymology. This species is named for Zegang Feng, who participated in field work and collected some of the specimens.

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–IV each with 2 setae. Pedipalps slender, femur 7.57–7.64 (♂), 7.71–8.21 (♀) times longer than broad; chela 7.00–7.29 (♂), 6.95–7.05 (♀) 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. Males (holotype and paratypes) ( Figs 6E View FIGURE 6 , 7A View FIGURE 7 , 8A–D View FIGURE 8 , 9 View FIGURE 9 ).

Colour ( Figs 6E View FIGURE 6 , 7A View FIGURE 7 , 8A–D View FIGURE 8 ): generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.

Cephalothorax ( Figs 8B View FIGURE 8 , 9A View FIGURE 9 ): carapace 1.00–1.02 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 12–13 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 View FIGURE 9 ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 8C View FIGURE 8 , 9B View FIGURE 9 ): large, about as long as carapace, 2.33–2.43 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 14–15 teeth, distal one largest; movable finger with 12–13 retrorse contiguous small teeth; galea completely vestigial ( Fig. 9B View FIGURE 9 ). Serrula exterior with 21–23 and serrula interior with 13–14 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. 9D View FIGURE 9 ).

Pedipalp ( Figs 8A View FIGURE 8 , 9E–G View FIGURE 9 ): long and slender, trochanter 1.69–1.73, femur 7.57–7.64, patella 2.18–2.44, chela 7.00–7.29, hand 2.86–3.05 times longer than broad; femur 2.74–2.86 times longer than patella; movable chelal finger 1.38–1.44 times longer than hand and 0.58–0.59 times longer than chela. Setae generally long and acuminate; 1 distal lyrifissure present on patella ( Fig. 9E View FIGURE 9 ). 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 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, t situated between est and it and distal to b; est situated distal to b ( Fig. 9F View FIGURE 9 ). 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 teeth present in the middle of the row, becoming smaller and closer distally and proximally: fixed chelal finger with 23–25 macrodenticles, slightly retrorse and pointed, plus 14– 15 intercalary microdenticles and a modified accessory tooth on dorso-antiaxial face (td, near tip), 38–41 in total; movable chelal finger with 17–19 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, plus 11– 12 intercalary microdenticles and 11–13 vestigial, rounded and contiguous basal teeth, 41–42 in total ( Fig. 9F View FIGURE 9 ). Fixed chelal finger with sensilla af 1–2 close together, near tip; movable chelal finger with 4 sensilla: am 1–2 near tip, p 1 slightly distad of sb and very close to chelal teeth, p 2 proximad of sb ( Fig. 9F View FIGURE 9 ). Chelal fingers slightly curved in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Fig. 9G View FIGURE 9 ).

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: 5: 5: 2: T2T: 0, tergites VIII and IX each with an unpaired median seta. Sternal chaetotaxy III–XII: 13–14: 12–13: 7–8: 7–9: 7–9: 8–9: 7–8: 6–7: 0: 2. Anterior genital operculum with 9 setae, genital opening slit-like, with 11–12 marginal setae on each side, 32 in total ( Fig. 8D View FIGURE 8 ).

Legs ( Fig. 9H, I View FIGURE 9 ): generally typical, long and slender. Fine granulation present on anterodorsal faces of femur I, IV and patella IV. Femur of leg I 1.94 times longer than patella and with 1 lyrifissure at the base of femur; tarsus 2.37–2.39 times longer than tibia. Femoropatella of leg IV 4.48–4.60 times longer than deep; tibia 6.20–6.67 times longer than deep; with a long tactile seta on both tarsal segments: basitarsus 4.29–5.00 times longer than deep (TS= 0.37), telotarsus 14.80–15.00 times longer than deep and 2.47–2.50 times longer than basitarsus (TS= 0.42–0.44). Setae of leg I (trochanter to tibia) 2–3: 9–11: 9: 12–13, setae of leg IV (trochanter to basitarsus) 2–3: 3: 5–6: 8–9: 8–10. Arolium slightly shorter than the claws, not divided; claws simple.

Adult females (paratypes) ( Figs 6F View FIGURE 6 , 7B View FIGURE 7 , 8E View FIGURE 8 ). Mostly same as males, but a little larger; chaetotaxy of coxae: P 3, I 3, II 3–4, III 5 , IV 5 ; tergal chaetotaxy I–XII: 2: 2: 2: 2: 4: 4: 5: 5: 5: 2: T2 T: 0; sternal chaetotaxy IV–XII: 12–13: 8: 8–9: 7–8: 8: 7: 6–7: 0: 2; anterior genital operculum with 9 setae, posterior margin with 14–15 marginal setae, 23–24 in total; leg IV with a long tactile seta on both tarsal segments: basitarsus 4.00–4.29 times longer than deep (TS= 0.37–0.43), telotarsus 15.20–15.40 times longer than deep and 2.57–2.71 times longer than basitarsus (TS= 0.41–0.44).

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 2.07–2.10. Pedipalps: trochanter 0.26–0.27/0.15–0.16 (1.69–1.73), femur 1.06–1.07/0.14 (7.57–7.64), patella 0.37–0.39/0.16–0.17 (2.18–2.44), chela 1.53–1.54/0.21–0.22 (7.00–7.29), hand 0.63–0.64/0.21–0.22 (2.86–3.05), movable chelal finger length 0.88–0.91. Chelicera 0.56/0.23–0.24 (2.33–2.43), movable finger length 0.30–0.31. Carapace 0.53/0.52–0.53 (1.00–1.02). Leg I: trochanter 0.17–0.18/0.12–0.13 (1.31–1.50), femur 0.60–0.62/0.08 (7.50–7.75), patella 0.31–0.32/0.07 (4.43–4.57), tibia 0.27–0.28/0.06 (4.50–4.67), tarsus 0.64–0.67/0.05–0.06 (11.17–12.80). Leg IV: trochanter 0.23–0.24/0.14 (1.64–1.71), femoropatella 0.92–0.94/0.20–0.21 (4.48–4.60), tibia 0.60–0.62/0.09–0.10 (6.20–6.67), basitarsus 0.30/0.06–0.07 (4.29–5.00), telotarsus 0.74–0.75/0.05 (14.80–15.00).

Females: body length 2.25–2.32. Pedipalps: trochanter 0.26–0.29/0.15–0.16 (1.73–1.81), femur 1.08–1.15/0.14 (7.71–8.21), patella 0.39–0.41/0.17 (2.29–2.41), chela 1.53–1.55/0.22 (6.95–7.05), hand 0.64/0.22 (2.91), movable chelal finger length 0.89–0.90. Chelicera 0.57–0.61/0.25–0.27 (2.26–2.28), movable finger length 0.31–0.32. Carapace 0.56–0.58/0.55–0.60 (0.97–1.02). Leg I: trochanter 0.17–0.18/0.13 (1.31–1.38), femur 0.60–0.64/0.08 (7.50–8.00), patella 0.31–0.32/0.07 (4.43–4.57), tibia 0.29–0.31/0.05 (5.80–6.20), tarsus 0.62–0.66/0.06 (10.33– 11.00). Leg IV: trochanter 0.25–0.27/0.15 (1.67–1.80), femoropatella 0.91–0.95/0.20–0.22 (4.32–4.55), tibia 0.61– 0.65/0.09–0.10 (6.50–6.78), basitarsus 0.28–0.30/0.07 (4.00–4.29), telotarsus 0.76–0.77/0.05 (15.20–15.40).

Remarks. Lagynochthonius fengi sp. nov. is similar to L. yaowangguensis sp. nov. in having the intercalary teeth on both chelal fingers and a pointed and triangular epistome, but differs by the shorter chela (e.g. chela length 1.53–1.54 vs. 1.84 mm, movable chelal finger length 0.88–0.91 vs. 1.15 mm; all in males) and the number of setae on tergites I–IV (2 vs. 4).

Lagynochthonius fengi sp. nov. differs from L. bailongtanensis in the shape of the epistome (pointed and triangular vs. rounded and obtuse), the pattern of dentation on the chelal fingers (with intercalary teeth on both chelal fingers vs. without intercalary teeth), and the number of setae on tergites I–IV (2 vs. 3–4)

Lagynochthonius fengi sp. nov. can be distinguished from L. laoxueyanensis by the presence of intercalary teeth on both chelal fingers, the number of setae on tergites III and IV (2 and 2, respectively vs. 4 and 4, respectively), and a larger body size (body length 2.07–2.10 vs. 1.78 mm in males) ( Li et al. 2019; Hou et al. 2022).

Distribution and habitat. This species is only known from the type locality, Unnamed Cave 2 ( Figs 1B View FIGURE 1 , 6A– D View FIGURE 6 ), which is located about 0.6 km west of Maliu Village (Yanjin County) near the top of a mountain. This limestone cave has a small and slit-shaped entrance (about 1 m high and 3 m wide) and only a narrow tunnel (approximately 80 m in length) leading to the deepest part of the cave, which is a slightly wider, low-temperature, high-humidity and completely lightless environment (temperature around 11°C, humidity over 90%). All of the specimens were collected under stones in the deepest part of the cave (deep zone).