Pachygnatha unciniformis sp. nov.

(NJ状ḋşƍ)

Figures 7–12, 13C, D, 14B, 15C, D, 16

Material examined. China: Yunnan province: Dali Bai Autonomous Prefecture, Cangshan Mountains, Yudai Road, 25°41′26″N, 100°8′2″E, 2494 m, holotype ♂, 25 September 2022, leg. Jinxin Liu, Zongguang Huang, Yun liang, Yingli Wen and Xujun Feng (HNU1068); Same collecting information as holotype, paratypes 1♂ 1♀ (HNU506, 507). China: Yunnan province: Diqing Tibetan Autonomous Prefecture, Weixi Lisu Autonomous County, Tacheng Town, Bazhu Village, 27°32′16″N, 99°28′E, 2329 m, paratypes 1♂ 1♀, 16 September 2022, leg. Jinxin Liu, Zongguang Huang, Yun liang, Yingli Wen and Xujun Feng (HNU508, 509).

Etymology. The specific epithet is derived from a Latin adjective, meaning “hook-shaped” and referring to the end of conductor.

Diagnosis. The male of P. unciniformis sp. nov. resembles those of P. amurensis, P. fengzhen, P. tenera and P. shengtangensis sp. nov. in having a coiled embolus and a twisting conductor (Figs 2A, B, 8A, B; Zhu et al. 2003, figs 45D, 43D, 49D), but P. unciniformis sp. nov. can be distinguished from the latter three by a hook-shaped distal end of the conductor (Fig. 8A, C) versus a slightly bent distal end in the latter three (Fig. 2A, C; Zhu et al. 2003, figs 45D, 43D, 49D); and by the base of the cheliceral fang with an outer cusp in males (Fig. 8E), versus the base of fang without an outer cusp in the latter three (Fig. 2E; Zhu et al. 2003, figs 45A, 43A, 49A). The female of P. unciniformis is similar to those of the above three species in having the same number of retromarginal teeth (Figs 5D, E, 11D, E; Zhu et al. 2003, figs 44E, 42D, 48E), but P. unciniformis sp. nov. can be distinguished from the latter three by triangular spermathecae (Fig. 11B), versus globular spermathecae in P. amurensis, P. tenera and P. fengzhen and kidney-shaped spermathecae in P. shengtangensis sp. nov.) (Fig. 5B; Zhu et al. 2003, figs 44G, 42F, 48G).

Description. Male. Holotype (HNU1068). Total length 5.25. Carapace 2.31 long, 1.73 wide, pear-shaped, dark brown (Fig. 7A). Head area much higher than thoracic area and eyes surrounded by black ocular tubercles (Fig. 7A, C). Cervical groove and radial groove obvious, black (Fig. 7A). Fovea arc-shaped (Fig. 7A). Chelicerae dark brown, with six promarginal and four retromarginal teeth, accompanied by a nuptial spur on the prolateral surface (Figs 8D– F, 9D–F). Promarginal teeth approximately equal in size. The first and second retromargin teeth much bigger than the other two (Figs 8D–F, 9D–F). Fang not very straight, slightly bent in its midsection, and with an outer cusp at the base (Figs 8D–F, 9D–F). Labium trapezoidal, wider than long, and with the anterior margin thickened (Fig. 7B). Maxilla far longer than wide (Fig. 7B). Sternum 1.33 long, 1.61 wide, same color as the carapace, with a lot of little pits, and bilaterally and posteriorly extending between coxae (Fig. 7B). Eyes subequal in size, ALE and PLE close together, slightly smaller than median eyes. Eye sizes and inter-distances: ALE 0.09; AME 0.10; PLE 0.10; PME 0.11; ALE-AME 0.21; AME-AME 0.13; PLE-PME 0.22; PME-PME 0.21; MOA length 0.33, anterior width 0.29, posterior width 0.37 (Fig. 7A). Legs long and slender, light yellow-brown. Femur IV with three dorsal trichobothria (Fig. 15C). Leg measurements: Ⅰ 7.87 (2.11, 0.63, 2.29, 1.85, 0.99); II 6.79 (1.96, 0.59, 2.04, 1.49, 0.71); III 4.47 (1.39, 0.49, 1.08, 0.97, 0.54); IV 5.70 (1.63, 0.45, 1.51, 1.39, 0.72). Abdomen: 2.75 long, 2.27 wide, oval, dorsum with two longitudinal lines of discontinuous brown patterns, along with several guanine silvery patches present in the dorsal, lateral and ventral surfaces (Fig. 7).

Pedipalp (Figs 8A–C, 9A–C, 13C, D, 14B). Tibia twice as long as wide in ventral view, with dorsal side much longer than ventral side (Figs 8A, C, 9A, C). The middle part of paracymbium swollen, wider than two ends, and possessing a small apophysis (Figs 8B, 9B). Cymbium strongly constricted in its midsection (Figs 8C, 9C). Embolus coiled for about one circle around the tegulum, with its distal third extending towards the top of cymbium. Embolic medial groove conspicuous, dividing the basal part of embolus into two sclerotised parts which coil more than half a turn, creating the illusion of two concentric circle (Figs 8A, 9A, 13C, D, 14B). Conductor well-developed, comprising a transverse cutinized part and a vertical spiral membranous part when viewed from above, and with a hook-shaped distal end when observed in ventral and retrolateral views (Figs 13C, D, 14B).

Female (HNU506). Somatic morphology similar to male (Fig. 10). Total length 3.72. Carapace 1.77 long, 1.34 wide. Sternum 0.99 long, 1.12 wide. Eye sizes and inter-distances: ALE 0.09; AME 0.07; PLE 0.09; PME 0.09; ALE-AME 0.15; AME-AME 0.13; PLE-PME 0.22; PME-PME 0.18; MOA length 0.28, anterior width 0.26, posterior width 0.35. Chelicera with five promarginal and four retromarginal teeth (Figs 11C–E, 12B–D). The fang straight, without an outer cusp and not curved as in male (Figs 11C–E, 12B–D). Femur IV with three dorsal trichobothria (Fig. 15D). Leg measurements: Ⅰ 6.91 (1.97, 0.57, 1.93, 1.58, 0.86); II 6.20 (1.80, 0.57, 1.73, 1.35, 0.75); III 4.05 (1.21, 0.43, 0.99, 0.87, 0.55); IV 5.36 (1.67, 0.41, 1.38, 1.29, 0.61). Abdomen: 1.92 long, 1.43 wide.

Female genitalia (Figs 11A, B; 12A). Genital fold twice wide as its length. Gonopore crevice-shaped. Spermathecae triangular, with bulged surrounding margins. Uterus externus contracted in the middle section.

Distribution: Known only from the type locality, China (Yunnan) (Fig. 16).