Oedignatha zham sp. nov.

Figs 5–8

Type material. Holotype ♂ (MHBUARA-2023-901-1), CHINA: Xizang Autonomous Region: Nyalam County, Zham Town (27.9682°N, 85.9724°E; 2352 m a.s.l.), 10.VIII.2023, leg. X. Guo, H. Zhang. Paratype: 1♀ (MHBUARA-2023-901-2), same data as holotype.

Etymology. The specific epithet is derived from the name of the type locality, noun in apposition.

Diagnosis. Males of O. zham sp. nov. are most similar to the males of O. platnicki Song & Zhu, 1998 in having a similar shaped retrolateral tibial apophysis and a distally sclerotized conductor, but can be distinguished by: 1) the retrolateral branch of the retrolateral tibial apophysis with an apical bifurcation (Figs 6C, 8C; vs. two tooth-like projections in O. platnicki, see Chen & Huang 2009: fig. 9); and 2) conductor with a blunt apex directed at 11-o’clock ventrally (Figs 6B, 8B; vs. angular apex directed at 2-o’clock ventrally in O. platnicki, see Song & Zhu 1998: fig. 2E, Chen & Huang 2009: fig. 8). Females resemble O. shaanxi in having short copulatory ducts and spherical bursae, but can be distinguished from the latter by: 1) the epigynal plate with a septum (Figs 7A, 8D; vs. without septum in O. shaanxi, see Chu et al. 2023a: fig. 2A); and 2) spermathecae small and oval (Figs 7B, 8E; vs. large and spherical in O. shaanxi, see Chu et al. 2023a: fig. 2B).

Description. Male (holotype, Figs 5A–B). Total length 7.00, carapace 3.61 long, 2.59 wide; abdomen 3.39 long, 2.04 wide. Carapace oval, reddish-brown. Cervical and radial grooves indistinct. Clypeal hump inconspicuous (Fig. 5A). Labium and endite reddish-brown. Sternum medially reddish-brown, marginally brown (Fig. 5B). Legs brown, distal ends of femora of legs Ⅰ and IV yellow. Chelicerae with three pro- and seven retromarginal teeth, basal retromarginal tooth bifurcated. Eye sizes and interdistances: AME 0.14, ALE 0.14, PME 0.10, PLE 0.11; AME–AME 0.22, AME–ALE 0.28, ALE–ALE 0.84, PME–PME 0.39, PME–PLE 0.29, PLE–PLE 1.19, ALE–PLE 0.13. Leg measurements: Ⅰ 11.44 (2.91, 1.17, 2.77, 2.80, 1.79), II 9.36 (2.59, 1.03, 2.13, 2.22, 1.39), III 8.08 (2.22, 0.91, 1.56, 2.11, 1.28), IV 11.32 (2.88, 1.04, 2.38, 3.17, 1.85); leg formula 1423. Tibial and metatarsal ventral spines depicted in Table 2. Abdomen oval, dorsum dark brown, dorsal scutum covering approximately 5/6 of abdomen (Fig. 5A).

Palp (Figs 6, 8A–C). Cymbium basoretrolaterally with shallow groove extending about 1/4 length of cymbium (Figs 6C, 8C). Retrolateral tibial apophysis with two branches, prolateral branch hook-shaped, pointing anteriorly in ventral view, retrolateral branch broad, apically bifurcated, higher sclerotization than prolateral branch (Figs 6C, 8C). Conductor beak-shaped in retrolateral view, with broad base and angular tip (Figs 6C, 8C). Embolus filamentous, originating from 6-o’clock position and extending clockwise to anterior part of conductor in ventral view (Figs 6B, 8B).

Female (paratype, Figs 5C–D). Same as male except for the following: total length 7.31, carapace 3.41 long, 2.41 wide; abdomen 3.90 long, 2.56 wide. Chelicerae with eight retromarginal teeth, basal tooth not bifurcated. Eye sizes and interdistances: AME 0.12, ALE 0.13, PME 0.09, PLE 0.11; AME – AME 0.17, AME – ALE 0.14, ALE – ALE 0.68, PME – PME 0.31, PME – PLE 0.28, PLE – PLE 1.04, ALE – PLE 0.14. Leg measurements: Ⅰ 10.99 (2.79, 1.03, 2.80, 2.76, 1.61), II 9.04 (2.47, 1.03, 1.93, 2.19, 1.42), III 8.00 (2.16, 0.92, 1.48, 2.11, 1.33), IV 10.92 (2.56, 0.94, 2.50, 3.11, 1.81). Tibial and metatarsal ventral spines depicted in Table 2. Abdomen oval, with incomplete dorsal scutum (Fig. 5C).

Genitalia (Figs 7, 8D–E). Epigynal plate sclerotized, with trapezoidal and membranous epigynal window divided medially by septum (Figs 7A, 8D). Copulatory ducts short and arched. Bursae globular. Spermathecae oval. Fertilization ducts narrow, roughly anteriad (Figs 7B, 8E).

Distribution. Known only from the type locality.