Amaurobius yaan Lin & Li, sp. nov.

Figs 4, 5, 6, 7B, 8E–H, 9

Type material. Holotype: ♁ (IZCAS-Ar44741), China, Sichuan, Ya'an, Baoxing County, Qiaoqi Vill., (30.37°N, 102.82°E), 3 VII 2004, Xiang Xu leg. Paratype: 1♀ (IZCAS-Ar44742), China, Sichuan, Aba, Wenchuan Co., Wolong Town, Wolongguan Village, (31.0087°N, 103.1598°E, 2032 m) 17 XI 2014, Shuqiang Li leg.

Etymology. The specific name refers to the type locality and is a noun in apposition.

Diagnosis. Amaurobius yaan sp. nov. resembles A. fenestralis (Ström, 1768) (cf. Figs 4, 5, 6, 7B, 8E–H and Zhang et al. 2008: 503, figs 1–5) in that the males have similar conductor, embolus and median apophysis (Figs 4A, B, 5A), and the females have similar spermathecae (Fig. 6B). However, this new species can be distinguished by the male retrolateral tibial apophysis triangular (Figs 4B, 5A, B; vs. retrolateral tibial apophysis digitiform in ventral view), and the dorsal process of dorsal tibial apophysis longer than mesal process (Figs 4A, B, 5B; vs. mesal process almost 3 times dorsal process); females can be separated by the median lobe excavated medially on anterior margins, as wide as long (Fig. 6A; vs. anterior margin of median lobe slightly recurved, wider than long), and the lateral lobes large (Fig. 6A; vs. lateral lobes small), and the epigynal plate without epigynal hood (Fig. 6A; vs. epigynal hood present).

Description. Male (holotype; Fig. 8E, F): Total length 8.6, carapace 4.5 long, 3.2 wide; abdomen 4.1 long, 3.2 wide. Eye sizes and interdistances: AME 0.12, ALE 0.16, PME 0.11, PLE 0.15; AME–AME 0.16, AME–ALE 0.33, PME–PME 0.29, PME–PLE 0.46, AME–PME 0.22, ALE–PLE 0.12. Leg measurements: I: 11.0 (3.0, 3.7, 2.7, 1.6); II: 10.4 (3.0, 3.5, 2.4, 1.5); III: 9.2 (2.7, 3.3, 2.2, 1.0); IV: 11.4 (3.2, 4.1, 2.8, 1.3).

Colouration (in alcohol). Carapace yellowish brown without flecks, sternum yellowish, chelicerae dark brown, maxillae and labium brown, dorsum of abdomen brown with two pairs of white spots in the anterior part, two pairs of chevrons in the posterior part, and venter brown with white lines in both lateral sides, legs yellowish without ring flecks, spinnerets yellowish.

Chelicera. With 4 promarginal and retromarginal teeth.

Palp (Figs 4A, B, 5A, B). Three apophyses present in lateral to dorsal portion of tibia: retrolateral tibial apophysis triangular, dorsal tibial apophysis with two processes: dorsal process triangle shaped, mesal lamellae, almost as long as dorsal process. Bulb almost oval. Conductor membranous, partly fused with tegulum; median apophysis spatulashaped, distinctly excavated on prolateral side; embolus short and conglutinates with the tegulum.

Female (paratype; Fig. 8G, H): Total length 9.2, carapace 4.0 long, 3.0 wide; abdomen 5.2 long, 4.4 wide. Eye sizes and interdistances: AME 0.13, ALE 0.19, PME 0.13, PLE 0.11; AME–AME 0.12, AME–ALE 0.30, PME–PME 0.32, PME–PLE 0.49, AME–PME 0.19, ALE–PLE 0.15. Leg measurements: I: 8.6 (2.4, 3.1, 1.9, 1.2); II: 7.9 (2.3, 3.0, 1.6, 1.0); III: 6.1 (1.7, 2.4, 1.3, 0.7); IV: 8.4 (2.2, 3.4, 1.9, 0.9).

Colouration (in alcohol). Colour and somatic morphology as in male, except as noted: carapace reddish-brown to black, sternum brown, chelicerae black, maxillae and labium black, legs brown.

Chelicerae. With 3 promarginal and 4 retromarginal teeth.

Epigyne and internal genitalia (Fig. 6A, B). Lateral lobes triangular, pointed and distant from each other; median lobe rectangular, excavated medially on anterior margins, as wide as long. Spermathecae elliptical and distant from each other, copulatory ducts tubular, fertilization ducts short and distinct.

Distribution. China (Sichuan, type locality; Fig. 9).