Figs 19–20
Type material. Holotype: male (Ar29679), Charakae Cave (6°53.687′N, 99°46.743′E, elevation 25 m), La Ngu District, Satun, Thailand, 16 October 2015, Q. Zhao, G. Zhou and Z. Chen leg. Paratypes: 2 females (Ar 29680– 29681), same data as holotype.
Etymology. The specific name is a Chinese pinyin word for cave (dòng xúe), in reference to the habitat of this species; noun.
Diagnosis. The species can be easily distinguished from all known congeners in the P. yichengicus species group by the combination of the following characters: the male PME strongly protruding anteriorly (arrow in Fig. 20 F), the very short male pedipalp trochanter apophysis (Figs 19 A–B), the absence of large dorsal sclerites subdistally on the procursus (Fig. 19 D) and the absence of branches on the appendix (Fig. 20 C).
Description. Male (holotype): Total length 3.56 (3.96 with clypeus), carapace 1.06 long, 1.20 wide, opisthosoma 2.50 long, 1.18 wide. Leg I: 26.4 (8.01 + 0.60 + 8.59+ 14.87+ 1.75), leg II: 19.68 (6.09 + 0.56 + 6.15 + 9.49 + 1.09), leg III: 20.18 (6.09 + 0.56 + 6.15 + 9.62 + 1.16), leg IV: 25.35 (4.81 + 0.55 + 4.10 + 6.86 + 0.90); tibia I L/d: 72. Distance PME-PME 0.34; diameter PME 0.05; distance PME-ALE 0.03; AME absent. Sternum wider than long (0.84/0.63). Habitus as in Figs 20 E–F. Carapace yellowish, with light brown marks medially; ocular area yellowish, with brown marks; sternum yellowish, with brown marks marginally. Legs yellowish, darker rings absent. Opisthosoma yellowish, without spots. Ocular area elevated, each eye triad on top of a laterally directed eye-stalk; PME strongly protruding anteriorly (Fig. 20 G). Thoracic furrow absent. Chelicerae as in Fig. 20 D, with a pair of proximo-lateral apophyses, a pair of distal apophyses, and a pair of indistinct frontal apophyses. Pedipalps as in Figs 19 A–B; trochanter with a short ventral apophysis; femur with a distinct ventral modification; procursus simple proximally but complex distally; bulbal apophyses as in Fig. 20 C; uncus with a scaly edge; appendix curved, with a scaly edge; embolus weakly sclerotized. Retrolateral trichobothrium of tibia I at 5%; legs with short vertical setae on tibiae, metatarsi and tarsi; without spines and curved setae; tarsus I with 6 distinct pseudosegments.
Female: Similar to male, habitus as in Figs 20 H–I. Total length 3.14 (3.40 with clypeus), carapace 0.95 long, 1.06 wide, opisthosoma 2.19 long, 1.09 wide. Distance PME-PME 0.19; diameter PME 0.05; distance PME-ALE 0.02; AME absent. Sternum wider than long (0.72/0.63). Ocular area without eye-stalks; PME less protruding than male PME. Epigynum (Fig. 20 A) with a knob. Vulva (Fig. 20 B) with a sclerotized anterior arch and two elliptic pore plates.
Variation: Unknown (leg I lost in the other specimen).
Distribution. Thailand (Satun, type locality; Fig. 21).
Natural History. The species was found in the aphotic zone inside the cave.