Lagynochthonius bailongtanensis, Li & Liu & Shi, 2019

Li, Yun-Chun, Liu, Huai & Shi, Ai-Min, 2019, A new cave-dwelling species of Lagynochthonius (Arachnida: Pseudoscorpiones: Chthoniidae) from Yunnan Province, China, Zootaxa 4571 (1) : -

Lagynochthonius bailongtanensis sp. nov.

( Figs 1–18 )

Type material. Holotype: male ( MSWU: Ms20181015-01), CHINA: Yunnan Province, Luoping County, Bailongtan Village, Qianfo cave , 24°51.966ʹ N, 104°17.374ʹ E, 1594 m, 28 February 2016, leg. Yun-chun Li. Paratypes: 27 adults (10 ♂, 17 ♀) in MSWU (Ms20181015-01) , 4 adults (2 ♂, 2 ♀) in MNHN (Ar-Ps146-02), all with same data as holotype. The cave is approximately 700 m long, and 2–5 m high. The types were collected from under stones about 200 m from the cave entrance .

Diagnosis. Lagynochthonius with troglobiont habitus; carapace without eyes or eyespots. Epistome small, rounded. Tergites II–VI each with 4 setae, medial setae longer than lateral setae. Pedipalps slender, femur 8.9–10.0 times longer than broad (length 1.30–1.58 mm), patella 2.4–2.5 times (length 0.43–0.55 mm), chela 8.5–10.2 times longer than broad, hand 3.9–4.2 times longer than broad.

Etymology. Named after the village of Bailongtan, near the type locality.

Description. Carapace, pedipalps and chelicerae brown, legs slightly yellowish. Carapace distinctly constricted posteriorly ( Fig. 3 ), 0.94–0.96 times longer than broad, anterior margin thin, finely denticulate, epistome very small, obtuse, one seta near its base on each side; no eyes or eyespots; chaetotaxy 6:4:4:2:2 (18), anterolateral setae much shorter than others.

Tergal chaetotaxy: male 3–4:4:4:4:4:4:4–5:4–5:4–5:4:T2T:0, female 4:4:4:4:4:4:4:4:4–5:4:T2T:0. Sternal setae III–XII: male, 8–10:10–11:12:12:12:10:9–10:9:0:2, female 8–9:12:10–11:11–12:10:10:10:9–10:0:2; sternites IX– X with unpaired median seta. Manducatory process pointed, with 2 distal setae, one long and the other slightly shorter. Setae P 5, coxa I 3–4, II 3–4, III 5, IV 5; intercoxal tubercle absent. Process of coxa I long and rounded at tip. Coxae II each with 9–11 spines, arranged in an arc, distal (middle) spines longest, spines incised for about half their length. Male and female genital opercula as illustrated ( Figs 17–18 ). Male anterior genital operculum ( Fig. 18 ) with 10 setae, genital opening slit-like, with 13–15 marginal setae on each side; female anterior genital operculum ( Fig. 17 ) with 11–12 setae plus 6 setae on posterior margin.

Chelicera ( Fig. 8 ) with 5 setae on palm, ventrobasal seta shorter than others, palm with moderate hispid granulation dorsally. Fixed finger with 23–25 small teeth, decreasing in size proximally; movable finger with 16– 17 small teeth. Spinneret not developed, but silk ducts present. Serrula exterior with 22–25 and serrula interior with 14 blades. Rallum composed of 8 blades ( Fig. 9 ), distal blade weakly recumbent basally, with fine barbules and set apart from the other blades, latter tightly grouped and with long pinnae.

Palp ( Figs 11–16 ) with weak granulation ventrally at base of femur and base of patella. Trochanter 1.6–1.9 times longer than broad, femur slightly widened distally, 8.9–10.0 times, patella 2.4–2.5 times longer than broad, femur 2.9–3.1 times longer than patella, chela 8.5–10.2 times longer than broad, hand 3.6–3.9 times longer than broad; movable finger 1.2–1.4 times longer than hand. Setal formula of femur 4–5:4:1:2:4–5:1. Chelal palm ( Figs 11, 14 ) gradually constricted towards fingers; dorsal surface with a single row of 3–4 chemosensory setae between trichobothria esb and ib / isb; distal paraxial seta of palm not enlarged. Fingers straight in dorsal view ( Fig. 14 ). Fixed finger with 18–22 macrodenticles, plus one tooth on antiaxial face ( Figs 12, 15 ), near trichobothria dx. Movable finger with 10 macrodenticles; base of finger with about 3–7 very low, vestigial teeth (without canals and therefore difficult to count accurately). Movable finger with 4 sensilla: am 1–2 near tip ( Fig. 13 ); p 1 slightly proximad of sb, p 2 well distad of sb; terminal tooth of movable finger not hooked; apodeme complex of movable finger strongly sclerotized. Movable finger with a row of 4 very weakly lanceolate setae antaxioventrally, extending from t to nearly half-way between st and sb ( Fig. 13 ).

Legs ( Figs 5–7 ) elongate. Fine granulation present on anterodorsal faces of femora I and IV and patella IV. Leg I: femur 9.3–9.9 times longer than deep and 1.9–2.2 times longer than patella, patella 4.1–5.2 times, tibia 5.0–5.4 times, tarsus 12.7–13.2 times longer than deep and 2.2–2.5 times longer than tibia. Leg IV: femur+patella 6.0–6.3 times, tibia 6.8–7.5 times longer than deep, basitarsus 3.9–4.6 times longer than deep, with a basal tactile setae (TS= 0.23–0.27), telotarsus 14.4–15.9 times longer than deep and 2.4–3.0 times longer than basitarsus, with a tactile seta near base (TS= 0.20–0.23).

Measurements (in mm): Male (holotype and paratypes). Body length 2.55–2.92; carapace (length/breadth) 0.66–0.72/0.71–0.75. Pedipalps: trochanter 0.31–0.34/0.16–0.19, femur 1.30–1.58/0.15–0.18, patella 0.43–0.55/ 0.18–0.22, length of chela 1.85–2.22, hand 0.86–0.92/0.23–0.25, length of movable finger 1.07–1.21. Leg I: femur 0.79–0.85/0.09–0.11, patella 0.39–0.41/0.09–0.11, tibia 0.34–0.38/0.07–0.09, tarsus 0.81–0.83/0.07–0.09. Leg IV: femur+patella 1.07–1.21/0.17–0.21, tibia 0.71–0.78/0.10–0.12, basitarsus 0.33–0.36/0.08–0.10, telotarsus 0.87– 0.92/0.06–0.08.

Female (paratypes). Body length 2.72–2.95; carapace (length/breadth) 0.59–0.68/0.62–0.72. Pedipalps: trochanter 0.32–0.37/0.19–0.22, femur 1.35–1.56/0.17–0.19, patella 0.45–0.53/0.19–0.20, length of chela 1.94– 2.03, hand 0.82–0.87/0.22–0.24, length of movable finger 1.09–1.17. Leg I: femur 0.73–0.75/0.08–0.10, patella 0.38–0.40/0.07–0.09, tibia 0.32–0.35/0.06–0.08, tarsus 0.78–0.82/0.05–0.07. Leg IV: femur+patella 1.08–1.13/ 0.18–0.21, tibia 0.62–0.69/0.09–0.11, basitarsus 0.29–0.33/0.07–0.08, telotarsus 0.84–0.89/0.06–0.07.

Figures

FIGURES 1–2. Lagynochthonius bailongtanensis sp. nov. 1 male; 2 female.

FIGURES 3–10. Lagynochthonius bailongtanensis sp. nov., male holotype. 3 carapace; 4 process of right coxa I, ventral view; 5 right leg I, lateral view; 6 right leg IV, lateral view; 7 apotele of right leg IV, lateral view; 8 right chelicera; 9 rallum of left chelicera; 10 coxal spines of left leg II. Scale lines 0.1 mm.

FIGURES 11–18. Lagynochthonius bailongtanensis sp. nov., male holotype (16), and paratypes (male 11–15, 18; female 17). 11 chela, antiaxial view; 12 tip of fixed finger, antiaxial view; 13 tip of movable finger, antiaxial view; 14 chela, dorsal view; 15 tip of fixed finger, dorsal view; 16 palp (minus chela), dorsal view; 17 female genital area; 18 male genital area. Scale lines 0.1 mm, 0.5 mm (fig 11).