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 6. Batraxis minor Wang and Yin , new species ( Figs 3 B, 5L, 8D–F) Type material (4 ♂♂, 16 ♀♀). Holotype : CHINA : ♂, labeled ‘ CHINA : Hainan, Ledong Hsien, Jianfengling N.R., Mingfenggu, 18°44'30"N , 108°50'29"E , rainforest, decaying log, 995 m , 26.i.2015 , Peng, Yin, Tu, Song, Shen, Zhou, Wang leg.’ Paratypes : CHINA : 1 ♂ , 5 ♀♀, same label data as holotype ; 2 ♂♂, 7 ♀♀, same data as previous material except ‘ 27.i.2015 ’; 4 ♀♀, same data as previous material except ‘ 23.i.2015 ’. Diagnosis of male. Body with sparse, minute pubescence in most areas; frons with shallow subantennal transverse sulcus; vertex lacking median pit; antennomeres IX as long as wide; pronotum with shallow median antebasal fovea and basal impression; all tibiae thin; protibiae lacking modifications, mesotibiae without apical spur; protrochanters protuberant ventrally; tergite IV with narrow basal sulcus; discal carinae long, close; with short marginal carinae; aedeagus relatively elongate. Description. Male ( Fig. 3 B). Body yellowish brown, with sparse, minute pubescence in most areas, length 1.37 mm . Head rectangular, as long as broad, HL = HW 0.32 mm , vertex glabrous, apical margin of frons and clypeus sparsely pubescent; vertex moderately convex, with pair of indistinct vertexal foveae; antennal tubercles low; frons flattened, with shallow subantennal transverse sulcus, lacking vertexal sulcus; each eye composed of about 30 facets; antennae relatively thick, antennomeres III–VII slightly elongate, VIII as long as wide, IX narrower than VIII, X transverse, XI largest, widest near base, then obliquely narrowing toward apex; median gular carina shallow, with two clearly separated distinct gular foveae. Pronotum slightly wider than long, PL 0.27 mm , PW 0.32 mm , with shallow median antebasal fovea and complete basal impression. Elytra wider than long, EL 0.40 mm ; EW 0.50 mm , with two pairs of shallow foveae at base. Protrochanters strongly protuberant at ventral margin ( Fig. 5 L). Abdomen wider than long, AL 0.38 mm , AW 0.45 mm , slightly narrowed at base; tergite IV (first visible tergite) sparsely pubescent, with broad, abrupt basal sulcus; discal carinae relatively long, close extending to one-third of tergal length, width between discal carinae 0.11 mm at apices; short marginal carinae extending to apical one-third of tergal length. Aedeagus ( Fig. 8 D–F) 0.24 mm in length, relatively elongate, parameres exceeding apex of median lobe, expanded at apex, each with three preapical setae; endophallus with pair of symmetric sclerites and weakly sclerotized structure connecting them. Female. Very similar to male in general appearance; protrochanters simple; each eye composed of about 30 facets. Measurements: BL 1.35 mm ; HL 0.31 mm ; HW 0.32 mm ; PL 0.27 mm ; PW 0.33 mm ; EL 0.41 mm ; EW 0.50 mm ; AL 0.36 mm ; AW 0.47 mm ; width between discal carinae of tergite IV 0.10 mm at apices. Comparative notes. Batraxis minor is unique by the small body size ( 1.37 mm ) and largely reduced subantennal transverse sulcus, when combined with the structure of the aedeagus, this species can be readily separated from all other congeners from Hainan. Distribution. Southern China : Hainan. Etymology. The specific epithet refers to the small body size.