Pholcus songkhonensis Yao & Li sp. nov.

Figs 29–30

Type material. Holotype: male, Tham (cave) Bo Pla Cave (14°39.625′N, 100°58.115′E, elevation 73 m), Song Khon Village, Kaeng Koi District, Saraburi, Thailand, 20 October 2014, H. Zhao, Y. Li and Z. Chen leg. Paratypes: 2 males and 3 females, same data as holotype.

Etymology. The specific name refers to the type locality; adjective.

Diagnosis. This species resembles P. kaebyaiensis sp. nov. (Figs 25–26) and P. m u s e n s i s sp. nov. (Figs 27–28) in having similar male chelicerae (Fig. 30 D), uncus (Fig. 30 C), and female external genitalia (Fig. 30 A) but can be distinguished by the presence of long eye-stalks on the male ocular area (as in P. tharnlodensis sp. nov., cf. Fig. 31 A), by a pointed, sclerotized retrolateral apophysis distally on the procursus (arrow in Fig. 29 D), by the narrow prolatero-distal membranous process on the procursus (arrow in Fig. 29 C); also distinguished from P. musensis sp. nov. by the strongly protruding medially anterior arch of the vulva (Fig. 30 B) and by the presence of an angular median branch on the appendix (Fig. 30 C).

Description. Male (holotype): Total length 3.87 (4.10 with clypeus), carapace 1.06 long, 1.33 wide, opisthosoma 2.81 long, 0.94 wide. Leg I: 44.22 (10.64 + 0.58 + 11.03 + 20.03 + 1.94), leg II: 29.96 (7.82 + 0.59 + 7.69 +12.56 + 1.30), leg III: 21.07 (6.09 + 0.55 + 5.19 + 8.27 + 0.97), leg IV: 27.11 (7.88 + 0.55 + 6.60 + 10.90 + 1.18); tibia I L/d: 92. Distance PME-PME 0.38; diameter PME 0.10; distance PME-ALE 0.03; distance AME- AME 0.04; diameter AME 0.04. Sternum wider than long (0.88/0.70). Habitus as in Figs 30 E–F. Carapace yellowish, with yellow marks extending to ocular area; ocular area yellowish; sternum yellowish. Legs yellowish, distal parts of tibiae whitish, darker rings absent. Opisthosoma yellowish, without spots. Ocular area elevated; each eye triad on top of a long, laterally directed eye-stalk (as in P. tharnlodensis sp. nov., cf. Fig. 31 A). Thoracic furrow absent. Chelicerae as in Fig. 30 D, with a pair of proximo-lateral apophyses, a pair of black distal apophyses, and a pair of small frontal apophyses. Pedipalps as in Figs 29 A–B; trochanter with a short ventral apophysis; femur with a distinct ventral modification; procursus simple proximally but complex distally; uncus with a scaly edge; appendix hooked, with an angular median branch; embolus weakly sclerotized. Retrolateral trichobothrium of tibia I at 6.8%; legs with short vertical setae on tibiae, metatarsi and tarsi; without spines and curved setae; tarsus I with approximately 13 distinct pseudosegments.

Female: Similar to male, habitus as in Figs 30 G–H. Total length 3.94 (4.23 with clypeus), carapace 1.02 long, 1.06 wide, opisthosoma 2.92 long, 1.02 wide; tibia I: 10.13; tibia I L/d: 84. Distance PME-PME 0.17; diameter PME 0.11; distance PME-ALE 0.02; distance AME-AME 0.03; diameter AME 0.04. Sternum wider than long (0.85/0.75). Ocular area without eye-stalks. External genitalia (Fig. 30 A) with a short knob. Vulva (Fig. 30 B) with a sclerotized anterior arch and two long pore plates.

Distribution. Thailand (Saraburi, type locality; Fig. 32).

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