Euochin tianhe Wang & Zhang 2023, sp. nov.

Euochin tianhe sp. nov. (Rãƙẅss)

Figs 154–169

Type material. Holotype: ♁ (MHBU-ARA-00025239), CHINA: Gansu Province, Tianshui City, Maiji District, Quxi Forest Park (曲ĀAIJȑȁ), 34.248973°N, 106.012613°E, 1433 m a.s.l., 9 August 2021, leg. Z. Li & R. Zhang. Paratypes: 2♀ (MHBU-ARA-00025240), same data as holotype.

Etymology. The specific epithet is derived from the word “Tianhe” (meaning the river flowing from sky) in the ancient myth of Tianshui City (the type locality of the new species). Noun in apposition.

Diagnosis. Males can be easily distinguished from all known congeners by the presence of the flag-like embolic apophysis (Figs 159–162, 166). The female epigyne resembles that of Euochin lingyi sp. nov. and E. nanjiabawa sp. nov., but the three species can be distinguished by: (1) the shapes of the epigynal windows (wider than long in E. nanjiabawa sp. nov. and E. tianhe sp. nov., while longer than wide in E. lingyi sp. nov.); (2) the distances between the copulatory openings (close to each other in E. lingyi sp. nov. and E. tianhe sp. nov., while far away in E. nanjiabawa sp. nov.); (3) the trajectories of the copulatory ducts (running antero-laterally from the spermatheca in E. nanjiabawa sp. nov. and E. tianhe sp. nov., while running posteriorly in E. lingyi sp. nov.); and (4) the sizes of the fertilization ducts (much larger in E. nanjiabawa sp. nov. and E. tianhe sp. nov., while smaller in E. lingyi sp. nov.) (cf. Figs 83–84, 87–88, 115–116, 119–120, 164–165, 168–169).

Description. Male. Habitus see Figs 154,156.Carapace length 1.549; abdomen length 1.468. Eye measurements: AME 0.297, ALE 0.191, PME 0.068, PLE 0.169. Leg measurements: I 2.060 (0.605, 0.326, 0.474, 0.321, 0.334), II 1.879 (0.652, 0.249, 0.364, 0.264, 0.350), III 2.264 (0.742, 0.334, 0.398, 0.433, 0.357), IV 2.691 (0.880, 0.289, 0.560, 0.574, 0.388); leg formula: 4312. Color in ethanol: carapace dark brown, covered with yellow and white setae. Abdomen dark brown, covered with yellow and white setae. Chelicera (Fig. 158) with two promarginal and one retromarginal teeth. Palp (Figs 159–162, 166–167): distal femur and patella with long white setae; embolic disc relatively small, partly hidden by tegulum in ventral view; embolus tapered, with a blunt embolic flange ventrally; cymbial flange notably extended; RTA finger-like.

Female. Habitus see Figs 155, 157. Carapace length 1.646; abdomen length 1.642. Eye measurements: AME 0.380, ALE 0.234, PME 0.085, PLE 0.182. Leg measurements: I 2.391 (0.731, 0.398, 0.577, 0.373, 0.312), II 2.150 (0.712, 0.376, 0.469, 0.297, 0.296), III 2.582 (0.861, 0.304, 0.534, 0.424, 0.459), IV 3.211 (0.997, 0.382, 0.686, 0.590, 0.556); leg formula: 4312. Color in ethanol: like that of male, but abdomen darker in coloration. Chelicera as in male. Epigyne (Figs 163–165, 168–169): epigynal window wider than long; copulatory opening located centrally at posterior margin of epigynal window; copulatory duct short, with obvious accessory gland; spermatheca ovoid; fertilization duct large.

Distribution. China (Gansu).