Otacilia arcuata Mu & Zhang 2021, sp. nov.

Otacilia arcuata sp. nov. (弧形Dzḇü)

Fig. 6

Type material. Holotype ♂ (HN181103-01): CHINA: Hunan Province, Zhangjiajie City, Shangzhi County, Maoxi Town, Xiaozhuangping village, Tianping Mountain Reserve (29°47′30.24″N, 110°05′15.61″E, 1408 m), 3 Nov. 2018, leg. Yannan Mu.

Paratype: 1♀, with same data as holotype.

Etymology. This specific name is derived from the word “arcuate”, referring to the arc-shaped copulatory duct of the epigyne in ventral view; adjective.

Diagnosis. The new species resembles O. microstoma Wang et al., 2015, but males can be distinguished by the small tegular apophysis (vs larger) (compare Fig. 6D–F with fig. 2C–E in Wang et al. 2015), and females by the transverse glandular appendage (vs absent) and the long and semi-circular copulatory duct (vs V-shaped) (compare Fig. 6G–H with fig. 2F–G in Wang et al. 2015). Further, males can be distinguished from O. dentigera sp. nov. by the embolus straight and slanted (vs curved transversely) and the RTA slightly wider at the middle (vs narrow), and females by the copulatory duct short, curved and semi-circular (vs long and circular) and the spermathecae transverse as opposed to slanted.

Description. Male (Holotype). Total length 3.03; carapace 1.44 long, 1.24 wide; abdomen 1.59 long, 1.05 wide. The central area and margin of carapace yellow, black at middle, higher at central area. Cervical groove and radial groove indistinct. Eye sizes and interdistances:AME 0.08, ALE 0.08, PME 0.08, PLE 0.08; AME–AME 0.04, AME–ALE 0.02, ALE–ALE 0.21, PME–PME 0.10, PME–PLE 0.06; PLE–PLE 0.37, ALE–PLE 0.08. MOA 0.23 long, anterior width 0.19, posterior width 0.28. Clypeal height 0.16. Chelicerae brown, with three promarginal and two retromarginal teeth. Sternum yellow. Legs yellow, with black lateral annuli near distal end of femora and tibiae. Measurements of legs: I 5.32 (1.41, 0.48, 1.20, 1.51, 0.72), II 3.54 (0.96, 0.37, 0.69, 0.95, 0.57), III 4.37 (1.17, 0.48, 1.06, 1.06, 0.60), IV 5.23 (1.42, 0.53, 1.49, 1.27, 0.52). Spination: femora I–IV d1b, femur I pl 1111, femur II pl 11, tibia I v 22222, tibia II pv 111111 rv 11111, metatarsus I pv 1111 rv 111, metatarsus II pv 1111 rv 111. Abdomen oval, black and gray, with thin yellow dorsal scutum anteriorly, and five black stripes in dorsal view.

Palp as in Fig. 6D–F. RTA moderately long, triangular in retrolateral view, with small tooth at base and blunt tip. Tibia with sclerotized subtriangular prolateral apophysis (Fig. 6D). Bulb pyriform, sperm duct wide and strongly sclerotized; tegular apophysis small; embolus moderately long, transverse, slanted retrodistally; conductor absent.

Female (Paratype): total length 3.32; carapace 1.49 long, 1.29 wide; abdomen 1.83 long, 1.21 wide. Eye sizes and interdistances:AME 0.08, ALE 0.09, PME 0.08, PLE 0.09; AME–AME 0.04, AME–ALE 0.02, ALE–ALE 0.22, PME–PME 0.11, PME–PLE 0.05, PLE–PLE 0.36, ALE–PLE 0.07. MOA 0.21 long, anterior width 0.20, posterior width 0.28. Clypeal height 0.12. Measurements of legs: I 5.32 (1.39, 0.56, 1.57, 1.22, 0.58), II 4.44 (1.18, 0.51, 1.14, 1.09, 0.52), III 3.86 (1.06, 0.43, 0.77, 1.03, 0.57), IV 5.29 (1.44, 0.46, 1.06, 1.56, 0.77). Spination: femora I–IV d1b, femur I pl 11111, femur II pl 11, tibia I pv 111111 rv 1111111, tibia II v 222222, metatarsus I v 2222, metatarsus II pv 1111 rv 111. Abdomen with black inverted triangular spot and two gray triangular spots anteriorly, four black chevron stripes posteriorly. Other characters as in male, except larger body size.

Epigyne as in Fig. 6G–H. Epigynal plate poorly sclerotized, slightly transparent. Copulatory openings small, copulatory ducts short, curved as arc-shaped, covered by bursae in dorsal view; glandular appendages short, visible in ventral view; bursae large, balloon-shaped and transparent; spermathecae clavate, transverse; fertilization ducts short, oblique, located at anterior of spermathecae.

Distribution. China (Hunan Province) (Fig. 8).