Belisana muruo 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 : 115-120

Belisana muruo Yao & Li sp. nov.

Figs 5–6 , 11 C–D

Type material. Holotype: Male ( IZCAS Ar39801), Unnamed cave (28°47 ꞌ 17.99 ꞌꞌ N, 98°31 ꞌ 04.98 ꞌꞌ E, elevation 3427 m), 8 km east of Da Zhengtong , Muruo Village , Zhuwagen Town, Zayu County, Tibet, China, 6 September 2014, J. Liu leg. Paratypes: 2 males ( IZCAS Ar39802–39803) and 4 females ( IZCAS Ar39804–39807), same data as holotype .

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

Diagnosis. This species resembles B. mainling Zhang, Zhu & Song, 2006 (see Zhang et al. 2006: 203, figs 32–40) with similar bulbal apophyses ( Fig. 6C ) and vulval pore plates ( Figs 6B , 11D ), but can be distinguished by presence of large subdisto-prolateral sclerite (arrow in Fig. 5C ) and retrolateral membranous flap (arrow f in Fig. 5D ) on procursus. Unlike B. mainling male cheliceral distal apophyses face each other mesially (arrow da in Fig. 6D ), and epigynal pockets are more separated (arrow ep in Figs 6B , 11D ).

Description. Male (holotype, IZCAS Ar39801): Total length 2.13 (2.19 with clypeus), carapace 0.94 long, 0.78 wide, opisthosoma 1.19 long, 1.25 wide. Leg I: 7.41 (1.94 + 0.31 + 2.06 + 2.44 + 0.66), leg II: 5.54 (1.44 + 0.19 + 1.41 + 2.34 + 0.16), leg III: 3.23 (0.78 + 0.13 + 0.88 + 1.25 + 0.19), leg IV: 4.18 (1.31 + 0.19 + 1.03 + 1.34 + 0.31); tibia I L/d: 36. Habitus as in Figs 6 E–F. Carapace pale, with pair of large brown marks; ocular area with brown stripe medially; sternum pale, without marks. Legs pale, without darker rings. Opisthosoma grey, with black spots dorsally and laterally. Distance PME-PME 0.10, diameter PME 0.07, distance PME-ALE 0.04, AME absent. Ocular area barely elevated. Thoracic furrow absent. Clypeus unmodified. Sternum slightly longer than wide (0.63/0.53). Chelicerae ( Fig. 6D ) with pair of small proximo-lateral apophyses and pair of short, pointed distal apophyses each with hardened and pointed tip (distance between tips: 0.14). Pedipalps as in Figs 5 A–B; coxa unmodified; trochanter with short ventral apophysis provided with large retrolateral apophysis (arrow in Fig. 5B ); femur with indistinct proximo-dorsal apophysis (arrow in Fig. 5A ); procursus ( Figs 5 A–D) simple proximally and complex distally, with large subdisto-prolateral sclerite (arrow in Fig. 5C ), long, curved distal spine and retrolateral membranous flap (arrow f in Fig. 5D ); bulb ( Fig. 6C ) with hooked apophysis and simple embolus. Retrolateral trichobothria of tibia I at 17% proximally; legs with short vertical setae on tibiae, without spines or curved setae; tarsus I with 21 distinct pseudosegments.

Female (IZCAS Ar39804): Similar to male, habitus as in Figs 6 G–H. Total length 2.06 (2.19 with clypeus), carapace 0.88 long, 0.63 wide, opisthosoma 1.18 long, 1.09 wide. Tibia I: 2.66; tibia I L/d: 27. Distance PME-PME 0.10, diameter PME 0.06, distance PME-ALE 0.04, AME absent. Sternum slightly longer than wide (0.63/0.56). External female genitalia ( Figs 6A , 11C ) simple and flat, with pair of indistinct pockets 0.18 apart (ep in Figs 6B , 11D ). Vulva ( Figs 6B , 11D ) with wavy anterior arch and pair of elliptic pore plates.

Variation: Tibia I in one male paratype ( IZCAS Ar39802; leg I missing in another male paratype IZCAS Ar39803): 2.56. Tibia I in two female paratypes ( IZCAS Ar39805–39806; leg I missing in the other female paratype IZCAS Ar39807): 1.92, 2.56 .

Natural history. The species was found in the aphotic zone inside the cave.

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

Remarks. This new species was found within cavities of rock walls inside the cave, while the other species in this paper were found on the underside of rocks in epigean environments. In contrast with these other longlegged species, this new species has remarkably short legs. This discrepancy probably reflects adaptation to different microhabitats.

Figures

FIGURE 5. Belisana muruo sp. nov., holotype male. A–B. Pedipalp (Bulb removed) (A. Prolateral view, arrow points at proximo-dorsal apophysis on pedipalpal femur; B. Retrolateral view, arrow points at retrolateral apophysis on pedipalpal trochanter); C–D. Distal part of procursus (C. Prolateral view, arrow points at large subdisto-prolateral sclerite; D. Retrolateral view). f = flap, pr = procursus. Scale bars: 0.10 (A–B), 0.05 (C–D).

FIGURE 6. Belisana muruo 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.