Otacilia biarclata sp. nov. (Figs 1–20)

Material examined. Holotype ♂, China, Hainan Province, Ledong County, Mt. Jianfengling, Main Peak (18°43′47″N, 108°52′21″E), 31 January 2015, Li-Na Fu leg. Paratypes: 7♂, 2♀, Chi Jin, Bao-Shi Zhang leg., other data as holotype .

Etymology. The specific name comes from the Latin word ‘ arc ’, combined with the prefix ‘ bi -’, referring to the two arc-shaped copulatory ducts; adjective.

Diagnosis. Among the congeners, the new species is characteristic in having two arc-shaped copulatory ducts; and long sickle-shaped embolus. It resembles O. sinifera Deeleman-Reinhold, 2001 in having similar copulatory ducts, but can be distinguished by: 1) longer and thicker embolus; 2) copulatory openings anteriorly; 3) wooden-stick-shaped bursae. The female of the new species can be separated from O. limushan, O. jianfengling and O. bawangling by: 1) absence of median plate; 2) smaller copulatory openings; 3) wooden-stick-shaped bursae.

Description. Male (Fig. 7). Total length 3.05–3.25 (n =8). Holotype body 3.12 long; carapace 1.43 long, 1.23 wide; abdomen 1.58 long, 0.98 wide. Carapace dark brown, oval, abruptly narrow anteriorly, medium brown; thoracic part slightly higher than the cephalic part; fovea longitudinal, distinct. In dorsal view, AER slightly recurved, PER slightly wider than AER and almost straight. Diameter of eyes: AME 0.07, ALE 0.09, PME 0.08, PLE 0.06. Interdistances of eyes: AME–AME 0.04, AME–ALE 0.02, PME–PME 0.07, PME–PLE 0.04. MOA 0.24 long, front 0.20 wide, back 0.23 wide. Clypeus 0.10 high. Chelicerae with two strong anterior bristles (Fig. 1); cheliceral promargin with two well-separated teeth and retromargin with two clustered denticles (Fig. 4). Labium slightly wider than long (Fig. 2). Legs light brown. Leg measurements: leg I 5.52 (1.59, 0.37, 1.56, 1.26, 0.74), II 4.04 (1.12, 0.31, 1.01, 0.90, 0.70), III 3.75 (1.16, 0.25, 0.91, 0.76, 0.67), IV 5.99 (1.61, 0.43, 1.45, 1.51, 0.99). Leg formula: 4123. Femora I–IV basally with one dorsal spine. Femur I with four prolateral spines (Fig. 5) and femur II without prolateral spine; tibia I with six or seven proventral spines and seven retroventral spines, tibia II with six proventral spines and five retroventral spines; metatarsus I with four pairs of ventral spines, metatarsus II with four proventral spines and three retroventral spines; metatarsi III and IV with distal preening brush (Fig. 6). Abdomen dark brown; anterior half without a dorsal scutum; posterior half dark brown, with a white spot terminally.

Palp (Figs 9–12, 15–18). Palp with a thick, posteriorly extending RTA, consisting of a broad base and a hook-shaped tip; femur with an distal apophysis and a retrolateral concavity; distal cymbium ventrally with several hairs; tegulum convex, TA short and small; embolus strong, hook-shaped, slightly sharp apically.

Female (Fig. 8). Total length 3.45–4.03 (n =2). One paratype body 4.03 long; carapace 1.84 long, 1.61 wide; abdomen 2.24 long, 1.41 wide. Carapace light brown, oval, abruptly narrow anteriorly. Diameter of eyes: AME 0.08, ALE 0.07, PME 0.09, PLE 0.08. Eye interdistances: AME–AME 0.05, AME–ALE 0.04, PME–PME 0.09, PME–PLE 0.06. MOA 0.28 long, front 0.21 wide, back 0.29 wide. Clypeus 0.09 high. Chelicerae light brown. Labium and gnathocoxae brown. Legs and palps yellowish brown. Leg measurements: I 6.22 (1.52, 0.51, 1.86, 1.46, 0.87), II 5.26 (1.20, 0.54, 1.42, 1.21, 0.89), III 4.76 (1.15, 0.49, 1.04, 1.25, 0.83), IV 7.27 (1.95, 0.58, 1.76, 1.87, 1.11). Leg formula: 4123. Femora I–IV basally with one dorsal spine. Femur I with four prolateral spines and femur II with two prolateral spines; tibia I with seven pairs of ventral spines, tibia II with seven proventral spines and six retroventral spines; metatarsi I and II with the same spination as male. Abdomen without a narrow dorsal scutum. Other characters as in male.

Epigyne (Figs 13–14, 19–20). Copulatory openings small, oval, anteriorly (Figs 13, 19). Vulva anteriorly with a pair of large transparent wooden-stick-shaped bursae, posteriorly with a pair of thick, closely situated spermathecae; copulatory duct relatively long; glandular appendage much shorter than fertilization duct.

Distribution. China (Hainan).