On a collection of Batraxis Reitter (Coleoptera: Staphylinidae: Pselaphinae) from Hainan Island, southern China Author Wang, Dan Author Yin, Zi-Wei Author Wang, Chun-Xin text Zootaxa 2016 4109 1 1 15 journal article 39133 10.11646/zootaxa.4109.1.1 4dcea233-45e7-4c56-a91c-e97d6c250262 1175-5326 258822 5AA87F55-DE88-419B-98D4-ECDC3AE09FAE 4. Batraxis spinosas Wang and Yin , new species ( Figs 2 B, 5D, E, J, 7D–F) Type material (6 ♂♂, 7 ♀♀). Holotype : CHINA : ♂, labeled ‘ CHINA : Hainan, Ledong Hsien (ffi÷ θ), Jianfengling N. R. (*RΚDאffiffiU), Mingfenggu (d¼☺), 18°44'30"N , 108°50'29"E , rainforest, decaying log, 995 m , 27.i.2015 , Peng, Yin, Tu, Song, Shen, Zhou, Wang leg.’. Paratypes : CHINA : 1 ♂ , 4 ♀♀, same label data as holotype ; 4 ♂♂, 3 ♀♀, same data except ‘ 26.i.2015 ’. Diagnosis of male. Body with sparse, minute pubescence in most areas; frons with abrupt subantennal transverse sulcus; vertex lacking median pit; antennomeres IX slightly elongate; pronotum with shallow median antebasal fovea and distinct basal impression; all tibiae thin; protibiae and mesotibiae with apical spur; protrochanters protuberant ventrally; tergite IV with narrow basal sulcus; discal carinae long, close; with relatively short marginal carinae; aedeagus relatively elongate. Description. Male ( Fig. 2 B). Body reddish-brown, length 1.87 mm . Head rectangular, slightly wider than long, HL 0.37 mm , HW 0.43 mm , vertex glabrous, apical margin of frons and clypeus sparsely pubescent; vertex moderately convex, with pair of small but distinct vertexal foveae; antennal tubercles low; frons flattened, with abrupt subantennal transverse sulcus, lacking vertexal sulcus; each eye composed of about 30 facets; antennae relatively thin, antennomeres III–IX slightly elongate, X transverse, XI largest, widest near base, then obliquely narrowing toward apex; median gular carina shallow, with two clearly separated small nude gular foveae. Pronotum slightly wider than long, PL 0.38 mm , PW 0.42 mm , with shallow median antebasal fovea and complete basal impression. Elytra wider than long, EL 0.57 mm , EW 0.67 mm , dorsal surface with sparse, minute setae, with pair of distinct foveae at base. Protrochanters strongly protuberant at ventral margin ( Fig. 5 J); protibiae and mesotibiae each with small apical tooth ( Fig. 5 D, 5E). Abdomen slightly wider than long, AL 0.52 mm , AW 0.60 mm , slightly expanded at base; tergite IV (first visible tergite) sparsely pubescent, with narrow basal sulcus; discal carinae relatively elongate, divergent, close at bases, extending to two-fifth of tergal length, width between carinae 0.10 mm at bases, 0.16 mm at apices; marginal carinae extending to apical one-third of tergal length. Aedeagus ( Fig. 7 D–F) 0.32 mm in length, relatively elongate, parameres distinctly exceeding apex of median lobe, apically narrowed, each with two preapical setae; endophallus with two pair of symmetric sclerites and spine-like structures at apex. Female. Very similar to male in general appearance; protrochanters, protibiae and mesotibiae lacking spur; each eye composed of about 30 facets. Measurements: BL 1.77 mm ; HL 0.40 mm ; HW 0.39 mm ; PL 0.37 mm ; PW 0.42 mm ; EL 0.52 mm ; EW 0.66 mm ; AL 0.48 mm ; AW 0.60 mm ; width between discal carinae of tergite IV 0.08 mm at bases, 0.12 mm at apices. Comparative notes. Batraxis spinosas is close to B. hainanensis by sharing the abrupt subantennal transverse sulcus, and slightly elongate antennomeres III–IX. These two species can be separated by the pronotal median antebasal fovea being reduced to a depressed area, presence of a complete, shallow basal impression, close discal carinae of tergite IV, pro- and mesotibiae each spinose apically, and aedeagus with long parameres and symmetric endophallus in B. spinosas . Batraxis hainanensis has a small but distinct median antebasal fovea on the pronotum, the basal impression is abrupt at the middle, the pro- and mesotibiae are simple, the discal carinae of tergite IV are more widely separated, and the aedeagus has shorter parameres and asymmetric endophallus. Distribution. Southern China : Hainan. Etymology. The specific epithet refers to the spinose apices of the male mesotibiae.