Sinostidia Yu & Li, 2021

Zhang, Jianshuang, Yu, Hao & Li, Shuqiang, 2021, On the clubionid spiders (Araneae, Clubionidae) from Xishuangbanna, China, with descriptions of two new genera and seven new species, ZooKeys 1062, pp. 73-122 : 73

Sinostidia Yu & Li gen. nov.

Type species.

Sinostidia shuangjiao Yu & Li, sp. nov.

Etymology.

The generic name is derived from the species’ similarity to Pristidia and the Latin adjective Sino - for Chinese, referring to the distribution of the genus. The gender is feminine.

Diagnosis.

This genus can be easily confused with Pristidia due to a similar appearance. Sinostidia gen. nov. and Pristidia share a similar cephalic region/carapace width ratio, relatively large eyes (PME barely> their diameter apart), tibial spination, and pale brownish body, but they can be separated by Sinostidia gen. nov. having promarginal teeth closer to the fang base than the retromarginal ones. The copulatory organs of Sinostidia gen. nov. resemble those of Pristidia in having a similar bulb with a sharply pointed embolus arising dorsally, hidden by the tegulum and by having a similar epigynal plate, but differ by: (1) the palpal tibia with 2 apophyses (Figs 21B , 23B ) (vs. 1 apophysis); (2) the distinct and heavily sclerotised tegular apophysis (Figs 21A-E , 23C-E ) (vs. tegular apophysis absent in almost all Pristidia species, or present but semi-transparent in P. cervicornuta ); (3) the epigyne with a large depression or atrium (Figs 22A, B , 24A, B ) (vs. depression and atrium lacking); (4) the spermathecae consist of a subglobular head and torsional base (Figs 22C, D , 24C, D ) (vs. spermathecae undivided).

Description.

Medium-sized, with body length of males 4.5-5.0, females 4.79-5.6. Body yellow-white, legs uniformly coloured as carapace. Carapace: elongate-oval in dorsal view, pars cephalica slightly elevated above thorax, pars thoracica distinctly wider than pars cephalica; integument smooth, with sparse, erect, thin, dark bristles on pars cephalica (bristles detach easily in ethanol); yellow or pale orange, slightly darker in ocular region, without distinct pattern; fovea longitudinal, reddish. Clypeus height distinctly less than diameter of AME. Chelicerae robust, brownish red, fang furrow with three promarginal and two retromarginal teeth. Sternum yellowish, anteriorly straight, anterior and lateral margins with brown extensions fitted into intercoxal concavities; posterior region strongly protruded between coxae IV. Eyes: arranged in a compact group; AER slightly recurved in dorsal view, procurved in anterior view, AME very slightly smaller than ALE, or equal in diameter, AME closer to ALE than to each other; PER recurved in dorsal view, PME distinctly larger than PLE, PME separated by one diameter. Legs: formula usually IV, I, II, III; all tarsi scopulate; anterior metatarsi with a pair of basal ventral spines; tibiae I and II with two pairs of strong ventral spines; tibiae and metatarsi of posterior legs with more spines than anterior legs, but spination varies among different individuals. Abdomen: lanceolate, tapered posteriorly, uniformly white, dorsum with numerous indistinct patches, or anteriorly with a longitudinal, grey heart mark; venter, sides white, without distinct markings. Spinnerets: anterior lateral spinnerets short and coniform; posterior lateral spinnerets cylindrical, relatively long; anterior median spinnerets small, sandwiched between anterior lateral spinnerets and posterior lateral spinnerets.

Male palp: Femur and patella unmodified. Tibia short, no longer than 1/2 of cymbium length, with two apophyses: ventral apophysis stout, with blunt tip, typically thumb-like; retrolateral apophysis weak, shape variable, tip relatively pointed. Cymbium unmodified, ~ 1.8 × longer than wide, with dense dorsal setae. Bulb elongate-oval, embolic area located distally on tegulum. Tegular apophysis large, longer than 1/2 of tegulum width, arising at ~ 1 o’clock position, gradually tapered toward apex, pointed prolatero-distally, covering embolic base. Embolus with bulky base and sharp tip, curved behind tegular apophysis, tip extended to apex of cymbium. Conductor small, situated retrolaterally on tegulum.

Epigyne: Plate with shallow, very large depression or atrium, covering> 80% of plate. Spermathecae situated anteriorly, with subglobular head and twisted base. Bursae situated posteriorly, surface wrinkled, ribbed, pigmented, sclerotised inside. Fertilisation ducts small, acicular, on distal end of spermathecal base.

Comments.

The large PME and the presence of a claw-shaped embolus located behind the tegulum indicate that the new genus is likely closely related to Pristidia . Somatic characters are either poorly delineated or variable, making the differentiation of Sinostidia gen. nov. and Pristidia difficult. However, the two new species share a distinct set of genitalic characters and can be easily separated from Pristidia , thus, we established a new genus to accommodate them.

Composition.

Two species, Sinostidia shuangjiao Yu & Li, sp. nov. (type species) and Sinostidia dujiao Yu & Li, sp. nov.

Distribution.

China (Yunnan).

Figures

Figure 21. Male palp of the holotype of Sinostidia shuangjiao sp. nov. A prolateral view B retrolateral view C bulb, prolateral view D bulb, ventral view E bulb, retrolateral view. Abbreviations: C = conductor; E = embolus; EB = embolic base; RTA = retrolateral tibial apophysis; TA = tegular apophysis; VTA = ventral tibial apophysis. Scale bars: 0.10 mm (equal for A, B, equal for C-E).

Figure 22. Sinostidia shuangjiao sp. nov., female paratype and male holotype, epigyne (A-D), male habitus (E, F) and female habitus (G, H) A intact, ventral view B cleared, ventral view C cleared, dorsal view D cleared, dorsal view E dorsal view F lateral view G dorsal view H ventral view. Abbreviations: BS = bursa; CD = copulatory duct; CO = copulatory opening; SB = spermathecal base; SH = spermathecal head; SP = spermatheca. Scale bars: 0.10 mm (equal for A-D); 1 mm (equal for E, F, equal for G, H).

Figure 23. Male palp of the holotype of Sinostidia dujiao sp. nov. A prolateral view B retrolateral view C bulb, prolateral view D bulb, ventral view E bulb, retrolateral view. Abbreviations: C = conductor; E = embolus; EB = embolic base; RTA = retrolateral tibial apophysis; TA = tegular apophysis; VTA = ventral tibial apophysis. Scale bars: 0.10 mm (equal for A, B, equal for C-E).

Figure 24. Sinostidia dujiao sp. nov., female paratype and male holotype, epigyne (A-D), male habitus (E, F) and female habitus (G, H) A intact, ventral view B cleared, ventral view C cleared, dorsal view D cleared, dorsal view E dorsal view F lateral view G dorsal view H ventral view. Abbreviations: BS = bursa; CD = copulatory duct; CO = copulatory opening; SB = spermathecal base; SH = spermathecal head; SP = spermatheca. Scale bars: 0.10 mm (equal for A-D); 1 mm (equal for E, F, equal for G, H).