Belisana xigaze Yao & Li, 2020

Zhu, Wenhui, Yao, Zhiyuan, Zheng, Guo & Li, Shuqiang, 2020, The Belisana spiders (Araneae: Pholcidae) from Tibet, China, Zootaxa 4802 (1), pp. 111-128 : 120-121

Belisana xigaze Yao & Li sp. nov.

Figs 7–8 , 11 E–F

Type material. Holotype: Male ( IZCAS Ar39808), Chentang Town (27°54'52.50"N, 87°28'51.54"E, elevation 3267 ± 3 m), Dinggye County, Xigaze, Tibet, China, 3 August 2014, Y. Li leg. Paratypes: 1 male ( IZCAS Ar39809) and 3 females ( IZCAS Ar39810–39812), same data as holotype .

Etymology. The specific name refers to the type locality and is a noun in apposition.

Diagnosis. This species resembles B. yadongensis ( Hu, 1985) (see Zhang et al. 2006: 203, figs 41–50) with similar male chelicerae ( Fig. 8D ) and bulbal apophyses ( Fig. 8C ), but males can be distinguished by presence of pointed dorsal projection on procursus ( Figs 7 A–D; round elevation in B. yadongensis ). The females may be distinguished by having roof-shaped vulval anterior arch ( Figs 8B , 11F ) and short vulval pore plates (arrow pp in Figs 8B , 11F ). Unlike B. yadongensis ( Hu, 1985) , there are black lateral margins and small median marks on carapace ( Figs 8 E–G) in both sexes.

Description. Male (holotype, IZCAS Ar39808): Total length 1.54 (1.61 with clypeus), carapace 0.63 long, 0.63 wide, opisthosoma 0.91 long, 0.70 wide. Leg I: 9.21 (2.49 + 0.26 + 2.69 + 3.21 + 0.56), leg II missing, leg III: 4.86 (1.54 + 0.25 + 1.09 + 1.47 + 0.51), femur IV: 1.86, other segments missing; tibia I L/d: 45. Habitus as in Figs 8 E–F. Carapace pale, with black lateral margins and small, brown median marks; sternum pale, without marks. Legs pale, without darker rings. Opisthosoma pale, with small black spots dorsally and laterally. Distance PME- PME 0.08, diameter PME 0.06, distance PME-ALE 0.03, AME absent. Ocular area not elevated. Thoracic furrow absent. Clypeus unmodified. Sternum approximately as long as wide (0.47). Chelicerae ( Fig. 8D ) with pair of small proximo-lateral apophyses and pair of long, curved distal apophyses each with hardened and pointed tip (distance between tips: 0.39). Pedipalps as in Figs 7 A–B; coxa unmodified; trochanter with short retrolatero-ventral apoph- ysis; femur without proximo-dorsal apophysis; procursus ( Figs 7 A–D) simple proximally and complex distally, protruding dorso-subdistally (arrow in Fig. 7A ), with distal membranous elements, slightly curved distal spine and large retrolateral membranous flap (arrow f in Fig. 7D ); bulb ( Fig. 8C ) with hooked apophysis and simple embolus. Retrolateral trichobothria of tibia I at 24% proximally; legs with short vertical setae on metatarsi, without spines or curved setae; tarsus I with 23 distinct pseudosegments.

Female (IZCAS Ar39810): Similar to male, habitus as in Figs 8 G–H. Total length 1.25 (1.33 with clypeus), carapace 0.47 long, 0.53 wide, opisthosoma 0.78 long, 0.66 wide. Tibia I: 1.35; tibia I L/d: 23. Distance PME-PME 0.12, diameter PME 0.07, distance PME-ALE 0.04, AME absent. Sternum approximately as long as wide (0.45). External female genitalia ( Figs 8A , 11E ) simple and flat, with pair of pockets 0.38 apart (ep in Figs 8 A–B, 11E–F). Vulva ( Figs 8B , 11F ) with roof-shaped anterior arch and pair of narrow, ear-shaped pore plates.

Variation: Leg I missing in the male paratype ( IZCAS Ar39809). Tibia I in one female paratype ( IZCAS Ar39811; leg I missing in another female paratype IZCAS Ar39812): 1.42 .

Natural history. The species was found on the underside of rocks.

Distribution. China (Tibet, type locality only; Fig. 12 ).

Figures

FIGURE 7. Belisana xigaze sp. nov., holotype male. A–B. Pedipalp (A. Prolateral view, arrow points at dorsal protruding part of procursus; B. Retrolateral view); C–D. Distal part of procursus (C. Prolateral view; D. Retrolateral view). b = bulb, e = embolus, f = flap, pr = procursus. Scale bars: 0.10 (A–B), 0.05 (C–D).

FIGURE 8. Belisana xigaze sp. nov., holotype male (C–F) and paratype female (A–B, G–H). A. External female genitalia, ventral view; B. Vulva, dorsal view; C. Bulb, prolateral view; D. Chelicerae, frontal view; E–H. Habitus (E, G. Dorsal view; F. Lateral view; H. Ventral view). b = bulb, ba = bulbal apophysis, da = distal apophysis, e = embolus, ep = epigynal pocket, pa = proximo-lateral apophysis, pp = pore plate. Scale bars: 0.05 (A–D), 0.40 (E–H).

FIGURE 11. Drawings of female genitalia in ventral and dorsal views. A–B. B. gyirong Zhang, Zhu & Song, 2006; C–D. B. muruo sp. nov.; E–F. B. xigaze sp. nov.; G–H. B. zham sp. nov. ep = epigynal pocket, pp = pore plate. Scale bars: 0.10.

FIGURE 12. Distribution records of five species of the genus Belisana. 1. B. gyirong Zhang, Zhu & Song, 2006; 2. B. medog sp. nov.; 3. B. muruo sp. nov.; 4. B. xigaze sp. nov.; 5. B. zham sp. nov.