Trachelas shilinensis, Zhang, 2017

Zhang, Feng, 2017, Four new species of the genus Trachelas L. Koch, 1872 and the first record of T. vulcani Simon, 1896 from South-West China (Araneae: Trachelidae), Zootaxa 4324 (1), pp. 23-49 : 44

Trachelas shilinensis sp. n.

Figs 17 , 18C–D

Type material. Holotype: ♀, CHINA: Yunnan Province: Kunming City, Shilin County, Stone Forest (24°54.220′N, 103°20.827′E), 1846m a.s.l., 30 June 2011, leg. Mingsheng Zhu . Paratypes: 1♀, Yunnan Province: Yuxi City, Eshan County, Linjiang Park (24°10.126′N, 102°23.880′E), 1615m a.s.l., 16 May 2011, leg. Zongxi Li. All specimens are deposited in MHBU .

Etymology. The species name is derived from the type locality; adjective.

Diagnosis. Among all the Old World Trachelas species, the new species resembles T. fanjingshan in having two impressions posteriorly on the epigynal plate and medially situated copulatory openings, but can be distinguished from it by: 1) the epigynal plate without an atrium, whereas with two large atria anteriorly in the latter species; 2) the impressions that are not triangular, as in T. fanjingshan ; 3) the copulatory ducts long and looping, whereas relatively short in the latter species; 4) the ST2 large and oval, whereas small and teardrop-shaped in T. fanjingshan ; 5) the ST1 dumbbell-shaped, whereas spherical in the latter. Male unknown.

Description. Female ( Figs 17 , 18C–D ). Total length 4.09–4.80 (n = 2). Holotype: body 4.09 long; carapace 1.70 long, 1.48 wide; abdomen 2.39 long, 1.54 wide. Carapace ( Fig. 17A ) dark brown, ovoid in dorsal view, truncate at posterior margin, highest at fovea, sparsely covered with tiny granulations. CRW 0.85, 0.57 times carapace width. Fovea dark brown, indistinct. Eyes ringed with black. AER and PER slightly recurved in dorsal view ( Fig. 17C ). Eye diameters: AME 0.10, ALE 0.10, PME 0.08, PLE 0.08. Eye interdistances: AME–AME 0.04, AME–ALE 0.01, PME–PME 0.08, PME–PLE 0.04, ALE–PLE 0.04. MOA 0.19 long, anterior width 0.21, posterior width 0.24. PERW 0.41, 0.8 times CRW. Clypeus height 0.09, slightly narrower than diameter of AME.

Chilum present ( Fig. 17D ). Chelicerae yellow-brown, granulated as the carapace, cheliceral boss pronounced, with three promarginal and two retromarginal teeth. Endites and labium ( Fig. 17B ) light yellow; endites without oblique depression; labium wider than long. Sternum light yellow, shield-shaped, with blunt precoxal triangles and intercoxal sclerites.

Legs light yellowish-brown, without cusps. Measurements of legs: I 3.23 (0.90, 0.35, 1.15, 0.70, 0.33); II 2.91(0.80, 0.40, 0.85, 0.58, 0.28); III 2.68 (0.75, 0.25, 0.78, 0.65, 0.25); IV 3.19 (0.86, 0.39, 0.98, 0.65, 0.30). Leg formula: 1423. Abdomen oval, pale grey, dorsal scutum absent, with two pairs of sigilla ( Fig. 17A ). Venter grey white, with two narrow lines of sclerotized spots, barely visible ( Fig. 17B ).

Epigyne ( Figs 17E , 18C ): poorly sclerotized, spermathecae and coiled ducts visible through translucent cuticle, with a pair of shallow impressions posteriorly; copulatory openings large, crescent-shaped, situated medially. Vulva ( Figs 17F , 18D ): copulatory ducts thick, long, looped from lateral side to inner side before entering ST2; ST2 large and oval, with gland pores, closely anterior to ST1; connecting ducts slender, coiled one loop medially; ST1 dumbbell-shaped, connected to a short, membranous FD.

Remarks. T. shilensis may be the unknown female of T. gigapophysis . It appears that there are some similarities in colouration between these two species, and the epigyne has some structural similarities (looping copulatory ducts, small posterior ST 2, curved/spiralling copulatory openings, posterior hood/impressions). Although the two species haven’t been collected together, the four localities form a “block” in western China.

Distribution. Known from two localities in the Yunnan Province ( Fig. 19 ).

Figures

FIGURE 17. Trachelas shilinensis sp. n., female, A. habitUs, dorsal view; B. same, ventral view; C. ocUlar area, dorsal view; D. cephalothorax, frontal view; E. epigyne, ventral view; F. vUlva, dorsal view. Scale bars: 1 mm (A – B); 0.2 mm (C – F).

FIGURE 18. A – B, Trachelas gaoligongensis sp. n., C – D, Trachelas shilinensis sp. n., A. epigyne, ventral view; B. vUlva, dorsal view; C. epigyne, ventral view; D. vUlva, dorsal view. Scale bars: 0.25 mm (A – D).

FIGURE 19. DistribUtion of new species and T. vulcani Simon, 1896 from SoUthwest China.