Figs 3–4, 5 E–F
Type material. Holotype: Male (IZCAS Ar41824), seasonal rainforest (21°24’11.50”N, 101°37’01.50”E, elevation 657 ± 15 m), Xishuangbanna Nature Reserve: Biological diversity corridor, Xiaolongha Village, Mengla County, Xishuangbanna, Yunnan, China, 29 June 2012, Zhigang Chen & Qingyuan Zhao leg. Paratype: 1 male (IZCAS Ar41825), same data as holotype.
Etymology. The specific name refers to the type locality and is a noun in apposition.
Diagnosis. This species resembles B. menglun Yao & Li, 2020 (see Zhu et al. 2020a: 334, figs 3–4) by the similar bulbal apophyses (Fig. 4A) but can be distinguished by the presence of a serrated subdisto-ventral sclerite (arrow 1 in Figs 3C, 5E), disto-prolateral spine (arrow 4 in Figs 3C, 5E), and narrow retrolateral membranous flap (arrow f in Figs 3D, 5F) on the procursus, and the male cheliceral distal apophyses are directed downward (arrow da in Fig. 4B; distal apophyses directed laterally in B. menglun).
Description. Male (holotype, IZCAS Ar41824): Total length 1.72 (1.88 with clypeus), carapace 0.78 long, 0.72 wide, opisthosoma 1.10 long, 0.63 wide. Leg I: 16.86 (4.23 + 0.26 + 4.36 + 6.73 + 1.28), leg II: 11.22 (3.21 + 0.25 + 2.76 + 4.17 + 0.83), leg III: 7.55 (2.24 + 0.19 + 1.92 + 2.69 + 0.51), leg IV: 9.70 (2.82 + 0.22 + 2.56 + 3.33 + 0.77); tibia I L/d: 70. Distance PME-PME 0.13, diameter PME 0.06, distance PME-ALE 0.09, AME absent. Sternum slightly wider than long (0.61/0.54). Habitus as in Figs 4 C–E. Carapace and sternum pale, without marks. Legs pale, without darker rings. Opisthosoma pale, without spots. Ocular area not elevated. Thoracic furrow absent. Clypeus unmodified. Chelicerae (Fig. 4B) with pair of small proximo-lateral apophyses and a pair of long, curved distal apophyses, each with sclerotized and pointed tip (distance between tips of distal apophyses: 0.47). Pedipalps as in Figs 3 A–B; coxa unmodified; trochanter with short retrolatero-ventral apophysis; femur with small proximodorsal apophysis (arrow in Fig. 3B); procursus (Figs 3 A–D, 5E–F) simple proximally but complex distally, with serrated subdisto-ventral sclerite (arrow 1 in Figs 3C, 5E), bifid subdisto-prolateral sclerite (arrow 2 in Figs 3C, 5E), long distal membranous lamella (arrow 3 in Figs 3C, 5E), disto-prolateral spine (arrow 4 in Figs 3C, 5E), and with narrow retrolateral membranous flap (arrow f in Figs 3D, 5F); bulb (Fig. 4A) with long, hooked apophysis and simple embolus. Retrolateral trichobothria of tibia I at 10% proximally; legs with short vertical setae on metatarsi, without spines and curved setae; tarsus I with 22 distinct pseudosegments.
Female: Unknown.
Variation: Tibia I in male paratype (IZCAS Ar41825): 4.56.
Natural history. The species was found on the underside of leaves and collected by canopy fogging.
Distribution. China (Yunnan, type locality only; Fig. 6).