Hypselistes arcus, Muhammad & Wang & Zhang, 2023

Muhammad, Irfan, Wang, Lu-Yu & Zhang, Zhi-Sheng, 2023, One new genus and nine new species of Linyphiidae spiders from Yintiaoling Nature Reserve, Chongqing of China, Zootaxa 5257 (1), pp. 82-114 : 94-97

Hypselistes arcus sp. n. (ƎŃDĦ)

Figures 11–13

Type material. Holotype male: CHINA: Chongqing, Wuxi County, YNR, Shuangyang Town, Tianchiba , 31.518383°N, 109.791014°E, elev. 1741m, 25.VI.2022, Tan Bing leg. (SWUC-T-LIN-28-01) . Paratypes (3 females): 1 female, YNR, Huangcaoping , 31°24′50.13″N, 109°55′40.2″E, elev. 2039 m, 24.VI.2022, Wang Lu-Yu leg. (SWUC-T-LIN-28-02) ; 2 females, YNR, Huangcaoping , 31°25'52.7952" N, 109°56'41.0028"E, elev. 2254 m, 22.VI.2022, Tan Bing leg. (SWUC-T-LIN-28-03~04) .

Etymology. This epithet derives from the Latin noun “ arcus ” meaning “arc” and referring to embolus arcshaped in male palp.

Diagnosis. Hypselistes arcus sp. n. can be distinguished from all other congeners by the male cephalic lobe present in the thoracic of the cephalothorax and PMEs not present on the cephalic lobe ( Fig. 13A, B ), vs., in all other congeners the cephalic lobe is present in the eye region and bears the PMEs on it ( Wiehle 1960, figs 154, 155, 162, 163); cephalic pits present in between the cephalic lobe in H. arcus sp. n. ( Fig. 13A, B ), vs., in all other congeners the cephalic pits present at the base of cephalic lobe ( Wiehle 1960, figs 154, 155, 162, 163). Male palp of H. arcus sp. n. can be distinguished from all other congeners by the following combination of characters, retrolateral tibial apophysis very long, almost overlapping 2/3 of the cymbium in retrolateral view; distal arm of paracymbium columnar with distal tip hook-shaped ( Fig. 11B ). The epigyne of H. arcus sp. n. can be distinguished from all other congeners by the ventral plate laterally with pair of depressions posteriorly ( Fig. 12A–C ).

Description. Male (holotype, Fig. 13A, B ): Total length: 2.23. Carapace 1.13 long, 0.74 wide, yellow, cephalic lobe 0.26 long, present in the thoracic of the cephalothorax, with parallel sulci containing cephalic pits in it that seem blocked with some sort of secretions (white arrows, Fig. 13A, B ); fovea, cervical and radial grooves distinct. Clypeus 0.21 high. Chelicerae with 5 promarginal and 4 retromarginal teeth. AER recurved, PER straight. Eye sizes and interdistances: AME 0.05, ALE 0.05, PME 0.05, PLE 0.06, AME–AME 0.04, PME–PME 0.06, AME–PME 0.08, AME–ALE, 0.05, PME–PLE 0.05, ALE–ALE 0.31, PLE–PLE 0.34, ALE–PLE contiguous. Length of legs: I 3.74 (1.09, 1.20, 0.92, 0.53), II 3.47 (1.01, 1.11, 0.86, 0.49), III 2.76 (0.81, 0.85, 0.71, 0.39), IV 3.68 (1.13, 1.20, 0.89, 0.51). TmI 0.97. Tibial spine formula: 1-1-1-1. Abdomen 1.20 long, 0.72 wide, oval, brownish-black, with pairs of sigillae, ventral side brown.

Palp (holotype, Fig. 11 A−D): Patella longer than tibia, ventrally grooved. Tibia cone-shaped in prolateral view, with 2 retrolateral and 1 dorsal trichobothria, retrolateral tibial apophysis long, apical end reaches the mid of cymbium in retrolateral view, dorsal tibial apophysis tongue-shaped; paracymbium J-shaped, distal arm columnar, tip hook-shaped; tegulum with conspicuous protegulum; distal suprategular apophysis robust, completely covering the median membrane. Embolic division: Embolus with 1.5 coils, extending above cymbial apex.

Female (one of paratypes, Fig. 13C ): Total length: 2.25. Carapace 0.85 long, 0.71 wide, yellow, posteriorly lateral margin with grey strip on each side, cephalic region slightly elevated; fovea, cervical and radial grooves distinct. Clypeus 0.21 high. Chelicerae with four promarginal and three retromarginal teeth. AER straight, PER slightly procurved. Eye sizes and interdistances: AME 0.04, ALE 0.07, PME 0.06, PLE 0.06, AME–AME 0.02, PME–PME 0.05, AME–PME 0.06, AME–ALE, 0.04, PME–PLE 0.04, ALE–ALE 0.28, PLE–PLE 0.31, ALE–PLE contiguous. Length of legs: I 2.19 (0.67, 0.76, 0.51, 0.26), II 2.12 (0.64, 0.75, 0.48, 0.25), III 1.79 (0.56, 0.61, 0.41, 0.21), IV 2.28 (0.68, 0.79, 0.55, 0.26). TmI 0.21. Tibial spine formula: 1-1-1-1. Abdomen 1.55 long, 1.09 wide, oval, greyish-black, with pairs of sigillae, ventral side black.

Epigyne ( Fig. 12 A−E): Ventral plate wider than long, posterior margin with pair of depression laterally; copulatory opening present posteriorly at the junction of dorsal and ventral plate. Dorsal plate reduced, triangular. Vulva: Copulatory ducts sinuous, forming three turns before entering the spermathecae. Spermathecae round, separated by the distance almost equals 2 times of their diameter; fertilization ducts long, extending mesally.

Distribution. Known only from the type locality.

Figures

FIGURE 11. Hypselistes arcus sp. nov., male holotype left palp. A prolateral view B retrolateral view C dorsal view D ventral view.

FIGURE 12. Hypselistes arcus sp. nov., female (one of paratypes). A, B Epigyne, ventral view, C Epigyne, posterior view, D Vulva, anterior view E Vulva, dorsal view. Arrows indicating the depression posteriorly in ventral plate.

FIGURE 13. Hypselistes arcus sp. nov., male holotype (A, B) and female paratype (C). A, C habitus, dorsal view B habitus, lateral view. Arrows indicate the cephalic secretions dried out in the cephalic lobe of holotype male.