Bisetocreagris cavernarum, Volker Mahnert & Yun-chun Li, 2016

Volker Mahnert & Yun-chun Li, 2016, Cave-inhabiting Neobisiidae (Arachnida: Pseudoscorpiones) from China, with description of four new species of Bisetocreagris Ćurčić, Revue suisse de Zoologie 123, pp. 259-268 : 261-262

Bisetocreagris cavernarum n. sp.

Figs 6-10

Holotype: MSWU; ♂; China, Chongqing, Bei Bei, Jin Dao Xia Town , Ert Long Cave , alt. 776 m, 30°05539’N 106°62385’E; 8 October 2015; coll. Yun-chun Li. The cave is about 1200 m long, 7 m high, with an underground river. Pseudoscorpions were collected by hand under rocks, together with some spiders.

Paratype: MHNG; 1♀; same data as for holotype.

Diagnosis: Troglobiomorphic habitus; carapace with 2 tiny plus 2 indistinct eyes; epistome absent; carapace with 6 setae on posterior margin, tergite I with 8-9 setae; teeth on movable cheliceral finger on thickened lamella, galea with several branches; pedipalp slender, smooth, excepted for fine granulation in distal half of hand; femur 5.8 times (length 1.92-2.1), patella 4.3- 4.7 times (length 1.78-2.01) longer than broad, pedicel (length 0.95-1.00) about half of total length of patella and as long as club, hand with pedicel 2.3 times (length 1.37-1.48), chela with pedicel 5.3-5.4 (length 3.27-3.51) times longer than broad, finger 1.4 (length 1.93-2.05) times longer than hand with pedicel. Trichobothrium est nearer to et than to isb, sb halfway between b and st.

Etymology: From the Latin word caverna (= cave), genitive plural (meaning coming from caves).

Description of holotype (paratype in parentheses): Pedipalps, chelicerae and anterior half of carapace yellowish red, carapace in basal half and tergites yellowish. Carapace smooth, 1.1 times longer than broad, anterior margin with a small rounded median knob, with 4 small eyes, 2 anterior eyes with indistinct lens, 1.5 diameters from anterior carapace margin, 2 posterior eyes indistinct and difficult to observe; with 27 (7-8-6- 6) (holotype) to 32 (8-11-7-6) (paratype) setae; tergites undivided, chaetotaxy: 8/9/ 10/10/11 / 13/13/12 / 13/11/8 (4 tactile setae) (9/8/9/9/ 11/12/12 / 13/10/12 /8). Manducatory process with 5 marginal setae, pedipalpal coxa with 7 (♀ 9-11) setae and 2 round lyrifissures (anteromedially, laterobasally), coxa I 7 (11) setae, lateral corner short and rounded, medial corner rectangular, II 9, III 5 /6 (6), IV 11 (12/13). Genital operculum with about 75 long acute setae, genital opening with 4/4 short acute interior setae, median genital sac undivided and short (reaching anterior half of sternite IV), wrinkled and with enlarged apex, lateral sacs wrinkled, dilated apically and bent anteriorly; sternite III with a small anteromedian groove (with 1/2 short setae at its margins) and with 22 setae (5 medial discal setae, not counting the tiny groove setae) (♀: 14) + 7/8 suprastigmal setae, IV 12 (11) + 2x 5, 16 (18)-17- 18 (16)-19 (17)-15 (16)-17(15)-6 (2 submedial tactile setae), submedial setae submarginally placed on VII-X. Pleural membrane granular.

Chelicera ( Fig. 6 ): Hand with 7 long, acute setae; fixed finger with about 16 small, acute, uniform teeth; movable finger with about 14 pointed teeth, the median ones on enlarged lamella, subgaleal seta reaching tip of galea. Galea ( Fig. 7 a, b) divided in 2 main branches (♂: left galea with one main branch broken), each one forked apically; serrula exterior with about 44-48 blades, serrula interior with about 34, distal blade not forked. Rallum ( Fig. 8 ) with 9 (8) pinnate setae, the first one with expanded base and separated from second one, proximal one shortest.

Pedipalp ( Figs 9-10 ): Femur and patella smooth, distal part of hand dorsally and medially finely granular; trochanter 2.5 (2.7) times, with a distinct small ventral hump, femur 5.8 (5.8) times, patella 4.3 (4.7) times, club 2.0 (2-4) times longer than broad, pedicel as long as or longer than club, hand with pedicel 2.3 (2.3) times, chela with pedicel 5.4 (5.3) times, without pedicel 5.0 (4.9) times longer than broad, finger 1.4 (1.4) times longer than hand with pedicel. Fixed finger with 121 (122) small conical uniform teeth, tooth row as long as on movable finger, movable finger with 119 (122) small teeth, in distal row part with small cusps, others rounded; a very short venom duct present in fixed finger. Trichobothria: eb-esb on lateral side of hand, ib-isb-ist grouped at level of b (movable finger), est nearer to et/it and proximal of st, sb on movable finger halfway between b and st.

Leg I: Femur 4.9 (5.5) times longer than deep and 1.5-1.6 times longer than patella; patella 4.1 (4.1) times, tibia 6.8 (6.3) times, basitarsus 3.9 (3.2) times, telotarsus 6.1 (4.7) times longer than deep and 1.6 (1.5) times longer than basitarsus.

Leg IV: Femur+patella 6.5 (6.5) times longer than deep, femur distinctly shorter than patella, tibia 9.4 (9.2) times, with one or two longer setae in distal half, basitarsus with a basal tactile seta, 4.0 (3.9) times, telotarsus with a tactile seta near middle of segment, 6.8 (5.6) times longer than deep and 1.5 times longer than basitarsus; claws long and slender, smooth, subterminal seta forked and dentate, arolia shorter than claws.

Measurements of holotype ♂ (paratype ♀ in parentheses): Body length 4.40 (5.03); carapace 1.17/10.05 (1.31/1.22). Pedipalp: trochanter 0.88/0.35 (1.01/0.38), femur 1.92/0.33 (2.10/0.36), patella 1.78/1.41 (2.01/0.43), pedicel length 0.95 (1.00); hand with pedicel 1.37/0.60 (1.48/0.66), length of pedicel 0.24 (0.27), finger length 1.93 (2.05), chela length with pedicel 3.27 (5.32), without pedicel 3.03 (3.24). Leg I: femur 1.11/0.23 (1.23/0.22), patella 0.75/0.18 (0.78/0.19), tibia 0.98/0.14 (1.03/0.16), basitarsus 0.47/0.12 (0.46/0.15), telotarsus 0.75/0.12 (0.71/0.15). Leg IV: femur+patella 1.87/0.29 (1.98/0.30), femur length 0.82 (0.88), tibia 1.74/0.18 (1.85/0.20), basitarsus 0.60/0.15 (0.61/0.16), telotarsus 0.90/0.14 (0.89/0.16).

Remarks: The new species, B. cavernarum , is most similar to B. chinacavernicola , sharing with this species a similar size, elongate pedipalps, a long patellar pedicel (about half of the total length of patella), 6 or 7 setae on posterior margin of carapace, and 8 or 9 setae on anterior tergites. Bisetocreagris cavernarum n. sp. differs from B. chinacavernicola , recorded from the caves Dei (=Xian Nin) and Chao-Tian (both near Huaying), by the presence of indistinct lenses on the 2 anterior eyes and the presence of 2 indistinct posterior eye-spots, by the fine granulation of the palpal hand, a more slender chela (without pedicel 4.9-5.0 vs 4.4-4.86 times longer than broad), the position of trichobothrium st which is distinctly nearer to t than to sb (halfway between sb and t in chinacavernicola ) and perhaps by shorter legs (e.g. femur+patella IV 1.87-1.98 vs 2.18).

Figures

Figs 1 - 10. (1 - 5) Bisetocreagris chuanensis n. sp., holotype ♂. (1) Left chelicera. (2) “ spinneret ” (broken?) of ♂ (a) and of ♀ (b). (3) Rallum. (4 - 5) Pedipalp (vestitural setae of chela fingers omitted), trochanter to patella (4) and hand (5). (6 - 10) Bisetocreagris cavernarum n. sp., holotype ♂. (6) Left chelicera. (7) Galea of ♂ (a) and of ♀ (b). (8) Rallum. (9 - 10) Pedipalp (vestitural setae of chelal fingers omitted), trochanter to patella (9) and hand (10). Scales: 0.5 mm (4 - 5, 9 - 10); 0.2 mm (2 - 3, 7 - 8; 1; 6).