Lagynochthonius jingshengensis, Sun, Guo & Zhang, 2024

Lagynochthonius jingshengensis sp. nov.

Chinese name. ÑȂȗ伪Dz

Figs 31–35 View FIGURE 31 View FIGURE 32 View FIGURE 33 View FIGURE 34 View FIGURE 35

Typematerial. Holotype ♂ (Ps.- MHBU-GX2021072901 ): China, Guangxi Zhuang Autonomous Region, Hechi City, Jingsheng Town, cave without name (Unnamed Cave 3) [23.973227°N, 108.29204°E], 609.6 m a.s.l., 29 July 2021, Zegang Feng, Hongru Xu, Liu Fu & Nana Zhan leg. GoogleMaps Paratypes: 1 ♂ (Ps.- MHBU-GX2021072902 ) and GoogleMaps 1 ♀ (Ps.- MHBU-GX2021072903 ), all with the same data as the holotype GoogleMaps .

Etymology. Named after the town of Jingsheng, near the type locality.

Diagnosis. (♂ ♀). Small sized hypogean species; carapace without eyes or eyespots, anterior margin smooth and epistome obtuse and small, round; tergites Ⅰ–ⅠⅠ each with two setae, tergites ⅠⅠⅠ–ⅠV each with four setae. Pedipalps slender, chela 6.50–6.92 (♂), 6.07 (♀) times as long as broad; femur 6.78–7.13 (♂), 6.20 (♀) times as long as broad; both chelal fingers without intercalary teeth and a modified accessory tooth (td) on prolateral-retrolateral face; chemosensory setae (sc) present on dorsum of chelal hand.

Description. Adult males (holotype and paratype) ( Figs 31A View FIGURE 31 , 32A–F View FIGURE 32 , 33 View FIGURE 33 , 34 View FIGURE 34 ).

Color generally pale yellow, chelicerae, carapace, pedipalps and tergites slightly darker black, soft parts pale.

Cephalothorax ( Figs 32D View FIGURE 32 , 33A View FIGURE 33 ): carapace nearly subquadrate, 1.00–1.09 times as long as broad, weakly constricted basally; posterior region with squamous sculpturing laterally, other area smooth, without furrows; anterior margin smooth, without serrations; epistome obtuse and small, round, without eyes or eyespots; with 18 setae arranged s4s: 4: 4: 2: 2, most setae heavy, long and gently curved, anterolateral setae much shorter than others; with three pairs of lyrifissures, first and second pair situated middle and flank to the setae of ocular row, third pair situated lateral to the sole pair of setae of posterior row. Manducatory process with two acuminate distal setae, anterior seta more than 1/2 length of medial seta; apex of coxa I with a rounded anteromedial process; coxae II with 8–10 terminally indented coxal spines on each side, set as an oblique and arc row, central spines slightly longer than the others ( Fig. 33D View FIGURE 33 ); intercoxal tubercle absent; chaetotaxy of coxae: P 3, I 3, II 4, III 5, IV 5.

Chelicera ( Figs 32C View FIGURE 32 , 33B View FIGURE 33 ): almost as long as carapace, 1.82–1.88 times as long as broad; five setae and two lyrifissures (exterior condylar lyrifissure and exterior lyrifissure) present on hand, all setae acuminate, ventrobasal setae shorter than others; movable finger with one medial seta. Cheliceral hand with moderate wrinkle on both ventral and dorsal sides. Both fingers well provided with teeth, fixed finger with 8–9 teeth, distal one largest; movable finger with 7–9 retrorse contiguous small teeth; galea completely vestigial ( Fig. 33B View FIGURE 33 ). Serrula exterior with 17–19 and serrula interior with 12–13 blades. Rallum with eight 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. 33C View FIGURE 33 ).

Pedipalp ( Figs 32A–B, 32E View FIGURE 32 , 33E View FIGURE 33 , 34A–B View FIGURE 34 ): trochanter 1.78–2.14, femur 6.78–7.13, patella 2.33–2.63, chela 6.50–6.92, hand 2.50–2.58 times as long as broad; femur 2.65–2.71 times as long as patella; movable chelal finger 1.60–1.65 times as long as hand and 0.61–0.62 times as long as chela. Setae generally long and acuminate. Chelal hand gradually constricted towards fingers, apodeme complex of movable chelal finger strongly sclerotized. 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 at base of fixed chelal finger; esb slightly distal eb and ist slightly distal to esb; it slightly distal to est, situated subdistally; et slightly near to tip of fixed chelal finger, slightly close to chelal teeth; dx situated distal to et; sb slightly closer to st than to b; b and t situated subdistally, t slightly distal to it and distal to b; est situated distal to b and close to it ( Figs. 32A View FIGURE 32 , 34A View FIGURE 34 ). Microsetae (chemosensory setae) present on dorsum of chelal hand ( Figs. 32B View FIGURE 32 , 34B View FIGURE 34 ). Both chelal fingers with a row of teeth, spaced regularly along the margin, teeth smaller distally and proximally: fixed finger with 17–19 well-spaced, pointed teeth, and a modified accessory tooth on prolateral-retrolateral face (td, slightly distal to dx); movable finger with 8–9 well-spaced, pointed teeth, plus 8–10 vestigial, rounded and contiguous basal teeth.

Opisthosoma: generally typical, pleural membrane finely granulated. All tergites and sternites undivided; setae uniseriate and acuminate. Tergal chaetotaxy I–XII: 2: 2: 4: 4–5: 4: 4: 4: 5: 5: 4: T2T: 0. Sternal chaetotaxy IV–XII: 12: 10: 9–10: 9–10: 10: 8–11: 9–11: -: 2. Genital region: sternite II with 6–8 setae scattered on median area, genital opening slit-like, sternite III with 12–18 setae ( Fig. 32F View FIGURE 32 ).

Legs ( Fig. 34C–D View FIGURE 34 ): fine granulation present on anterodorsal faces of femur IV and patella IV. Leg Ⅰ: femur 1.88–1.94 times as long as patella; tarsus 2.27–2.31 times as long as tibia. Leg IV: femoropatella 2.88–3.00 times as long as deep; tibia 4.88–5.33 times as long as deep; with basal tactile setae on both tarsal segments: basitarsus 2.50–3.00 times as long as deep (TS = 0.33–0.40), telotarsus 10.00– 12.33 times as long as deep and 2.47–2.67 times as long as basitarsus (TS = 0.30–0.32). Setae of leg I (trochanter to tibia) 3: 6–10: 7–8: 7–8, setae of leg IV (trochanter to basitarsus) 3: 2–3: 5–6: 9–10: 9–10. Arolium not divided, slightly shorter than the simple claws.

Adult female (paratype) ( Figs 31B View FIGURE 31 , 32G View FIGURE 32 ). Mostly same as males; tergal chaetotaxy Ⅰ–ⅩII: 2: 2: 4: 4: 4: 4: 4: 4: 5: 4: T2T: 0; sternal chaetotaxy IV–ⅩII: 6: 10: 10: 9: 9: 9: 9: -: 2. Genital region: sternite II with eight setae scattered on median area, sternite III with a row of six setae.

Dimensions (length/breadth or, in the case of the legs, length/depth in mm; ratios in parentheses). Males: body length 1.22–1.24. Pedipalps: trochanter 0.15– 0.16/0.07–0.09 (1.78–2.14), femur 0.57–0.61/0.08–0.09 (6.78–7.13), patella 0.21/0.08–0.09 (2.33–2.63), chela 0.78–0.83/0.12 (6.50–6.92), hand 0.30–0.31/0.12 (2.50– 2.58), movable chelal finger length 0.48–0.51. Chelicera 0.30–0.31/0.16–0.17 (1.82–1.88), movable finger length 0.16–0.17. Carapace 0.31–0.35/0.31–0.32 (1.00–1.09). Leg I: trochanter 0.10–0.12/0.07–0.08 (1.43–1.50), femur 0.30–0.31/0.05–0.06 (5.17–6.00), patella 0.16– 0.18/0.04–0.05 (3.60–4.00), tibia 0.15–0.16/0.04 (3.75– 4.00), tarsus 0.34–0.37/0.03–0.04 (9.25–11.33). Leg IV: trochanter 0.16/0.10–0.11 (1.45–1.60), femoropatella 0.48–0.49/0.16–0.17 (2.88–3.00), tibia 0.32–0.34/0.06– 0.07 (4.88–5.33), basitarsus 0.15/0.05–0.06 (2.50–3.00), telotarsus 0.37–0.40/0.03–0.04 (10.00–12.33).

Female: body length 1.33. Pedipalps: trochanter 0.16/0.10 (1.60), femur 0.62/0.10 (6.20), patella 0.21/0.10 (2.10), chela 0.85/0.14 (6.07), hand 0.34/0.14 (2.43), movable chelal finger length 0.51. Chelicera 0.33/0.19 (1.74), movable finger length 0.18. Carapace 0.36/0.34 (1.06). Leg I: trochanter 0.11/0.07 (1.57), femur 0.33/0.06 (5.50), patella 0.19/0.06 (3.17), tibia 0.16/0.04 (4.00), tarsus 0.39/0.03 (13.00). Leg IV: trochanter 0.16/0.10 (1.60), femoropatella 0.50/0.15 (3.33), tibia 0.34/0.07 (4.86), basitarsus 0.15/0.05 (3.00), telotarsus 0.40/0.04 (10.00).

Remarks. Lagynochthonius jingshengensis sp. nov. most closely resembles L. tuoluoensis in the absence of intercalary teeth, the presence of two setae on tergites I–II, the obtuse, small, round epistome and absence of eyes or eyespots on the carapace, but differs in following combination of characters: chelal finger 1.60–1.65 (♂) times longer than hand and fixed finger with 17–19 well-spaced, pointed teeth compared to chelal finger 1.56–1.59 (♂) times longer than hand and fixed chelal finger with 26– 27 macrodenticles in L. tuoluoensis ( Hou et al. 2023a) .

Ecology. All specimens were collected on the ground inside the cave.

Distribution. Known only from the type locality ( China, Guangxi Zhuang Autonomous Region).