Lagynochthonius spinulentus, 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 : 38-43

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.7251618
persistent identifier	https://treatment.plazi.org/id/8A6487A5-FFEB-A901-FF11-FAD0FD8AFBFE
treatment provided by	Plazi
scientific name	Lagynochthonius spinulentus
status	sp. nov.

Treatment

Lagynochthonius spinulentus sp. nov. (ØḦIJ伪oi)

Figs 27–30 View FIGURE 27 View FIGURE 28 View FIGURE 29 View FIGURE 30

Type material. Holotype ♂ (Ps.- MHBU-HBUARA#2021-41301 ): China, Yunnan Province, Zhenxiong County, Zhongtun Town, Qixin Village , Yingshan Cave , under stones within 20–200 m from the cave entrance [27°21′38.42″N, 104°49′16.72″E], 1709 m a.s.l., 28 September 2021, Zegang Feng, Yanmeng Hou, Lu Zhang & Liu Fu leg. GoogleMaps Paratypes: 2 ♂ (Ps.- MHBU-HBUARA#2021-41302 & HBUARA#2021-41303) , 2 ♀ (Ps.- MSWU-HBUARA#2021-41304 & HBUARA#2021-41305), all with the same data as the holotype GoogleMaps .

Etymology. The specific name is derived from the Latin word “ spinulentus ”, meaning spinous, which refers to the characters of more coxal spines.

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 8.39–8.81 (♂), 7.40–7.74 (♀) times longer than broad; chela 8.00–8.28 (♂), 7.34–8.42 (♀) times longer than broad; only fixed chelal finger with intercalary teeth and 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 27B View FIGURE 27 , 28A View FIGURE 28 , 29A–D View FIGURE 29 , 30 View FIGURE 30 ).

Colour ( Figs 27B View FIGURE 27 , 28A View FIGURE 28 , 29A–D View FIGURE 29 ): generally pale yellow, chelicerae, pedipalps and tergites slightly darker, soft parts pale.

Cephalothorax ( Figs 29B View FIGURE 29 , 30A View FIGURE 30 ): carapace 0.96–1.03 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 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, the second situated exterior 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 13–14 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. 30C View FIGURE 30 ); intercoxal tubercle absent; without sub-oral seta.

Chelicera ( Figs 29C View FIGURE 29 , 30B View FIGURE 30 ): large, about as long as carapace, 2.44–2.47 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 21–23 teeth, distal one largest; movable finger with 14–15 retrorse contiguous small teeth; galea completely vestigial ( Fig. 30B View FIGURE 30 ). Serrula exterior with 24–25 and serrula interior with 14–15 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. 30D View FIGURE 30 ).

Pedipalp ( Figs 29A View FIGURE 29 , 30E–G View FIGURE 30 ): long and slender, trochanter 1.70–1.94, femur 8.39–8.81, patella 2.57–2.84, chela 8.00–8.28, hand 3.08–3.19 times longer than broad; femur 2.61–2.80 times longer than patella; movable chelal finger 1.45–1.61 times longer than hand and 0.58–0.60 times longer than chela. Setae generally long and acuminate; 2 distal lyrifissures present on patella ( Fig. 30E View FIGURE 30 ). 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 at same level as est and distal to b ( Fig. 30F View FIGURE 30 ). 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 30–32 macrodenticles, slightly retrorse and pointed, plus 12– 13 intercalary microdenticles and a modified accessory tooth on dorso-antiaxial face (td, slightly distal to dx), 43–46 in total; movable chelal finger with 28–30 macrodenticles (slightly smaller than teeth on fixed chelal finger), slightly retrorse and pointed, without intercalary teeth but with a tubercle between fifth and sixth teeth ( Fig. 30F View FIGURE 30 ). 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 proximad of sb and very close to chelal teeth, p 2 distad of sb ( Fig. 30F View FIGURE 30 ). Chelal fingers straight in dorsal view; microsetae (chemosensory setae) present on dorsum of chelal hand ( Fig. 30G View FIGURE 30 ).

Opisthosoma: generally typical, pleural membrane finely granulated. Tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 2: 4: 4: 4: 5: 5: 5: 4: T2T: 0, tergites VII–IX each with an unpaired median seta. Sternal chaetotaxy III–XII: 13–15: 11–12: 8–9: 8: 9: 9: 9: 7: 0: 2. Anterior genital operculum with 10 setae, genital opening slit-like, with 11–13 marginal setae on each side, 33–35 in total ( Fig. 29D View FIGURE 29 ).

Legs ( Fig.30H, I View FIGURE 30 ): generally typical, long and slender.Fine granulation present on anterodorsal faces of trochanter IV, femur I, IV and patella I, IV. Femur of leg I 1.90–1.98 times longer than patella and with 1 lyrifissure at the base of femur; tarsus 2.18–2.21 times longer than tibia. Femoropatella of leg IV 4.11–4.17 times longer than deep; tibia 6.92–8.10 times longer than deep; with basal tactile setae on both tarsal segments: basitarsus 3.89–4.13 times longer than deep (TS= 0.27–0.29), telotarsus 15.17–16.33 times longer than deep and 2.76–2.80 times longer than basitarsus (TS= 0.25–0.29). Setae of leg I (trochanter to tibia) 2–3: 12–14: 10–11: 14–17, setae of leg IV (trochanter to basitarsus) 2–3: 3: 4–5: 10–13: 7–8. Arolium slightly shorter than the claws, not divided; claws simple.

Adult females (paratypes) ( Figs 28B View FIGURE 28 , 29E View FIGURE 29 ). Mostly same as males, but a little larger; chaetotaxy of coxae: P 3, I 3, II 4, III 5–6 , IV 5 ; with same tergal chaetotaxy as males; sternal chaetotaxy IV –XII: 10–12: 8: 8–9: 8–10: 9: 9: 7: 0: 2; anterior genital operculum with 10 setae, posterior margin with 10–13 marginal setae, 20–23 in total; leg IV with a long tactile seta on both tarsal segments: basitarsus 3.40–3.89 times longer than deep (TS= 0.26), telotarsus 13.43 times longer than deep and 2.69–2.76 times longer than basitarsus (TS= 0.28–0.33) .

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.98–2.05. Pedipalps: trochanter 0.33–0.34/0.17–0.20 (1.70–1.94), femur 1.41–1.51/0.16–0.18 (8.39–8.81), patella 0.54/0.19–0.21 (2.57–2.84), chela 2.07–2.16/0.25–0.27 (8.00–8.28), hand 0.77–0.86/0.25–0.27 (3.08– 3.19), movable chelal finger length 1.24–1.25. Chelicera 0.79–0.83/0.32–0.34 (2.44–2.47), movable finger length 0.42–0.43. Carapace 0.65–0.70/0.68 (0.96–1.03). Leg I: trochanter 0.21–0.25/0.16–0.17 (1.31–1.47), femur 0.80– 0.83/0.09–0.10 (8.30–8.89), patella 0.42/0.08–0.09 (4.67–5.25), tibia 0.38–0.39/0.07 (5.43–5.57), tarsus 0.83– 0.86/0.06–0.07 (12.29–13.83). Leg IV: trochanter 0.25–0.27/0.18 (1.39–1.50), femoropatella 1.15–1.21/0.28–0.29 (4.11–4.17), tibia 0.81–0.83/0.10–0.12 (6.92–8.10), basitarsus 0.33–0.35/0.08–0.09 (3.89–4.13), telotarsus 0.91– 0.98/0.06 (15.17–16.33).

Females: body length 2.33–2.75. Pedipalps: trochanter 0.39–0.40/0.20–0.21 (1.90–1.95), femur 1.47– 1.48/0.19–0.20 (7.40–7.74), patella 0.55–0.56/0.21–0.23 (2.39–2.67), chela 2.06–2.19/0.26–0.28 (7.34–8.42), hand 0.83–0.88/0.26–0.28 (2.96–3.38), movable chelal finger length 1.20–1.26. Chelicera 0.87–0.88/0.35–0.36 (2.42–2.51), movable finger length 0.46–0.48. Carapace 0.71–0.72/0.73–0.74 (0.96–0.99). Leg I: trochanter 0.22– 0.23/0.14–0.15 (1.47–1.64), femur 0.72–0.77/0.09–0.10 (7.70–8.00), patella 0.41–0.42/0.08 (5.13–5.25), tibia 0.38–0.40/0.08 (4.75–5.00), tarsus 0.83–0.89/0.06 (13.83–14.83). Leg IV: trochanter 0.31–0.32/0.19–0.20 (1.60– 1.63), femoropatella 1.16–1.20/0.27 (4.30–4.44), tibia 0.79/0.10–0.11 (7.18–7.90), basitarsus 0.34–0.35/0.09–0.10 (3.40–3.89), telotarsus 0.94/0.07 (13.43).

Remarks. Lagynochthonius spinulentus sp. nov. is similar to L. retrorsus sp. nov. in having intercalary teeth on the fixed chelal finger and a pointed, triangular epistome. It differs by the longer chela (e.g. chela length 2.07–2.16 vs. 1.57–1.61 mm, movable chelal finger length 1.24–1.25 vs. 0.93–0.96 mm; all in males), the dentation of the chelal fingers (the intercalary teeth small and pointed vs. round and obtuse, the teeth on movable chelal finger pointed and well-spaced vs. retrorse and contiguous) and the number of setae on tergites IV (4 vs. 2).

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

Lagynochthonius spinulentus sp. nov. differs from L. laoxueyanensis by the presence of intercalary teeth on both chelal fingers, the number of setae on tergites III (2 vs. 4), and a larger body (e.g. body length 1.98–2.05 vs. 1.78 mm, chela length 2.07–2.16 vs. 1.62 mm; all in males) ( Li et al. 2019; Hou et al. 2022).

Distribution and habitat. This species is only known from the type locality, Yingshan Cave ( Figs 1E View FIGURE 1 , 27A View FIGURE 27 ), which is located about 2 km northwest of Qixin Village (Zhenxiong County) and near the top of a mountain. This limestone cave has one small and square entrance (about 1 m high and 1 m wide), but a huge and downward sloping interior space. The ground is covered with silt. About 300 m of the cave have beenexplored but the total length of the cave is unknown. All of the specimens were collected under stones within 20 to 200 m from the cave entrance. The cool, high-humidity and dark interior environment (temperature around 14°C on average, humidity over 90%) is suitable for the survival of the species.