Batraxis tibialis Wang and Yin

Wang, Dan, Yin, Zi-Wei & Wang, Chun-Xin, 2016, On a collection of Batraxis Reitter (Coleoptera: Staphylinidae: Pselaphinae) from Hainan Island, southern China, Zootaxa 4109 (1), pp. 1-15 : 4

2. Batraxis tibialis Wang and Yin , new species

( Figs 1 B, 5B, 5F, 5H, 6D–F)

Type material (1 ♂, 1 ♀). Holotype: CHINA: ♂, labeled ‘ CHINA: Hainan, Qiongzhong Hsien, Limu Mt., nr., residence, 19°10'04"N, 109°44'45"E, decaying log, 625 m, 29.i.2015, Peng, Yin, Tu, Song, Shen, Zhou, Yan, Wang leg.’. Paratypes: CHINA: 1 ♀, same label data as holotype.

Diagnosis of male. Body almost glabrous; frons with abrupt subantennal transverse sulcus; vertex lacking median pit; antennomeres IX as long as wide; pronotum with distinct median antebasal fovea and complete basal impression; all tibiae thin; protibiae concaved and protuberant near apex, mesotibiae lacking apical spur; protrochanters protuberant ventrally; tergite IV with broad, abrupt basal sulcus; discal carinae short, widely separated; with short marginal carinae; aedeagus stout.

Description. Male ( Fig. 1 B). Body completely glabrous, reddish brown, length 1.92 mm. Head rectangular, slightly wider than long, HL 0.40 mm, HW 0.44 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 thick, antennomeres III–V slightly elongate, VI–IX as long as wide, IX smaller than VIII, X transverse, XI largest, widest near base, then obliquely narrowing toward apex; median gular carina narrow, with two clearly separated gular foveae. Pronotum slightly wider than long, PL 0.40 mm, PW 0.45 mm, with small nude median antebasal fovea and complete, shallow basal impression. Elytra wider than long, EL 0.54 mm, EW 0.76 mm, with two pairs of distinct foveae at base. Protrochanters strongly protuberant at ventral margin ( Fig. 5 H), protibiae distinctly concaved before apex, one small tooth at each side of the cavity ( Fig. 5 B), profemora with small ventral protuberance at middle ( Fig. 5 F). Abdomen wider than long, AL 0.58 mm, AW 0.71 mm, obliquely narrowed at base; tergite IV (first visible tergite) with broad, abrupt basal sulcus; discal carinae short, widely separated, extending to apical one-fifth of tergal length, width between discal carinae 0.34 mm at apices; short marginal carinae extending to apical one-fourth of tergal length. Aedeagus ( Fig. 6 D–F) 0.27 mm in length, stout, parameres each with three preapical setae; endophallus complicated, comprised with a series of asymmetric sclerites, and numerous fine spine-like structures at apex.

Female. Very similar to male in general appearance; legs lacking modifications; each eye composed of about 25 facets. Measurements: BL 1.95 mm; HL 0.42 mm; HW 0.43 mm; PL 0.38 mm; PW 0.44 mm; EL 0.52 mm; EW 0.74 mm; AL 0.63 mm; AW 0.72 mm; width between discal carinae of tergite IV 0.34 mm at apices.

Comparative notes. Batraxis tibialis can be readily separated by the presence of a small protuberance on the ventral margin of the profemora, preapically concaved protibiae with a small tubercle inside, combined with the stout aedeagus with asymmetric aedeagal endophallus. As far as is known, all other Batraxis species from Hainan lack such protuberance on the profemora and concavity on the protibiae.

Distribution. Southern China: Hainan.

Etymology. The specific epithet refers to the modified protibiae of the new species.

Figures

FIGURE 1. Dorsal habitus of Batraxis species. A. B. bicolor. B. B. tibialis. Scale line: 0.3 mm.

FIGURE 5. Diagnostic features of male Batraxis species. (A – D. Protibia. E. Mesotibia. F. Mesofemur. G – L. Protrochanter). A, G. B. bicolor. B, F, H. B. tibialis. C, I. B. pilosa. D, E, J. B. spinosas. K. B. hainanensis. L. B. minor. Scale line: 0.1 mm.

FIGURE 6. Aedeagi of Batraxis species. (A, D. in dorsal view. B, E. in lateral view. C, F. in ventral view). A – C. B. bicolor. D – F. B. tibialis. Scale line: 0.1 mm.