Belisana tarang Zhu & Li 2021, sp. nov.

Belisana tarang sp. nov.

Figs 11–12, 13K–L, 14I–J, 15F

Type material. Holotype: Male (IZCAS Ar41916), near entrance of Tarang Cave (0°12’39.18”N, 100°24’58.62”E, elevation 877 m), Bukittinggi, West Sumatra, Sumatra, Indonesia, 13 May 2014, Z. Yao leg. Paratypes: 1 male (IZCAS Ar41917) and 2 females (IZCAS Ar41918–41919), same data as holotype.

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

Diagnosis. This species resembles B. sandakan Huber, 2005 (see Huber 2005: 59, figs 360–375) with the same shape of the bulbal apophyses (Fig. 12D), but males can be distinguished by the presence of a nearly triangular subdisto-prolateral sclerite (arrow 1 in Figs 11C, 13K) and triangular retrolateral membranous flap (arrow f in Figs 11D, 13L) on the procursus (Figs 11A–D, 13K–L), and by having the cheliceral distal apophyses directed laterally (arrow da in Figs. 12C, 15F; distal apophyses directed downward in B. sandakan). Females can be distinguished by having the frontal “epigynal” pockets laterally on a sclerotized plate (arrow ep in Figs 12A–B, 14I–J) and a long vulval anterior arch, 2/3 of the vulva length (Figs 12B, 14J) (vs. short vulval anterior arch, 1/2 of the vulva length). It can also distinguished by a longer total body length (total body length <1.4, “tiny” size in B. sandakan, Huber 2005: 3).

Description. Male (holotype, IZCAS Ar41916): Total length 1.46 (1.54 with clypeus), carapace 0.63 long, 0.63 wide, opisthosoma 0.91 long, 0.69 wide. Leg I missing (see variation), leg II: 7.45 (2.03 + 0.25 + 1.88 + 2.63 + 0.66), leg III: 3.23 (0.88 + 0.13 + 0.88 + 1.09 + 0.25), leg IV: 5.07 (1.47 + 0.19 + 1.19 + 1.63 + 0.59). Distance PME-PME 0.06, diameter PME 0.08, distance PME-ALE 0.08, AME absent. Habitus as in Figs 12E–F. Carapace pale, with yellow median marks. Ocular area not elevated. Clypeus unmodified. Chelicerae (Figs. 12C, 15F) with pair of small proximo-lateral apophyses and pair of long, curved distal apophyses, each with sclerotized and pointed tip (distance between tips of distal apophyses: 0.23). Sternum pale, approximately as wide as long (0.38). Thoracic furrow absent. Legs pale, without darker rings. Opisthosoma pale, without spots. Palps as in Figs 11A–B; coxa unmodified; trochanter with short retrolatero-ventral apophysis; femur with small proximo-dorsal apophysis (arrow in Fig. 11B); procursus (Figs 11A–D, 13K–L) curved (arrow in Fig. 11A), complex distally, with large, nearly triangular subdisto-prolateral sclerite (arrow 1 in Figs 11C, 13K), small subdisto-dorsal sclerite (arrow 2 in Figs 11C, 13K), large distal membranous process (arrow in Figs 11D, 13L) and triangular retrolateral membranous flap (arrow f in Figs 11D, 13L); bulb (Fig. 12D) with short, hooked apophysis and simple embolus. Legs with short vertical setae on metatarsi, without spines and curved setae.

Female (IZCAS Ar41918): Similar to male, habitus as in Figs 12G–H. Total length 1.39 (1.47 with clypeus), carapace 0.47 long, 0.47 wide, opisthosoma 1.00 long, 0.94 wide. Tibia I: 1.75; tibia I L/d: 29. Distance PME-PME 0.07, diameter PME 0.06, distance PME-ALE 0.07, AME absent. Sternum slightly wider than long (0.38/0.34). External female genitalia (Figs 12A, 14I) simple and flat, with pair of frontal “epigynal” pockets (arrow ep in Figs 12A–B, 14I–J), 0.34 apart. Vulva (Figs 12B, 14J) with W-shaped anterior arch and pair of long, narrow pore plates (arrow pp in Figs 12B, 14J), without serrated sclerites.

Variation: In male paratype (IZCAS Ar41917): Leg I: 10.57 (2.66 + 0.28 + 2.72 + 3.75 + 1.16); tibia I L/d: 45. Retrolateral trichobothria of tibia Iat 7% proximally; tarsus Iwith 16 distinct pseudopodomeres.

Natural history. The species was found in leaf litter and collected by small plot direct searching.

Distribution. Indonesia (Sumatra, type locality only; Fig. 16).