Batraxis hainanensis 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 : 7

5. Batraxis hainanensis Wang and Yin , new species

( Figs 3 A, 5K, 8A–C)

Type material (48 ♂♂, 72 ♀♀). Holotype: CHINA: ♂, labeled ‘ CHINA: Hainan, Lingshui Hsien (Dz * θ), Diaoluoshan N.R. (ɷPMDאffiffiU), forest nr., residence, 18°44'N, 109°52'E, rainforest, decaying log, 1100 m, 04.ii.2015, Peng, Yin, Tu, Song, Shen, Zhou, Yan, Wang leg.’. Paratypes: CHINA: 6 ♂♂, 12 ♀♀, same label data as holotype; 3 ♂♂, 3 ♀♀, labeled ‘ China: Hainan, Qiongzhong Hsien, Limu Mt., path to peak, 19°10'27"N, 109°45'29"E, mixed forest, decaying log, 1000 m, 31.i.2015, Peng, Yin, Tu, Song, Shen, Zhou, Yan, Wang leg.’; 3 ♂♂, 8 ♀♀, same data as previous material except ‘ 01.ii.2015 ’; 14 ♂♂, 17 ♀♀, labeled ‘ China: Hainan, Ledong Hsien, Jianfengling N. R., Mingfenggu, 18°44'30"N, 108°50'29"E, rainforest, decaying log, 995 m, 23.i.2015, Peng, Yin, Tu, Song, Shen, Zhou, Wang leg.’; 2 ♂♂, same data as previous material except ‘ 25.i.2015 ’; 10 ♂♂, 22 ♀♀, same data as previous material except ‘ 26.i.2015 ’; 3 ♂♂, 6 ♀♀, same data as previous material except ‘ 27.i.2015 ’; 6 ♂♂, 4 ♀♀, labeled ‘ China: Hainan, Ledong Hsien, Jianfengling N.R., Yulingu (ffi ϔ ☺), 18°44'23"N, 108°55'35"E, broad-leaved forest, decaying log, 704 m, 27.i.2015, Peng, Yin, Tu, Song, Shen, Zhou, Yan, Wang leg.’.

Diagnosis of male. Body with sparse, minute pubescence in most areas; frons with abrupt subantennal transverse sulcus; vertex lacking median pit; antennomeres IX elongate; pronotum with small median antebasal fovea and abrupt basal impression; all tibiae thin; protibiae lacking modifications, mesotibiae without apical spur; protrochanters expanded slightly; tergite IV with narrow basal sulcus; discal carinae long, moderately close; with short marginal carinae; aedeagus relatively stout.

Description. Male ( Fig. 3 A). Body yellowish brown to dark-brown, length 1.87 mm. Head rectangular, almost as long as width, HL 0.40 mm, HW 0.39 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, vertexal sulcus lacking; each eye composed of about 30 facets; antennae thin, antennomeres III–IX slightly elongate, X transverse, XI largest, widest near base, then obliquely narrowing toward apex; median gular carina shallow, with two close indistinct gular foveae. Pronotum slightly wider than long, PL 0.35 mm, PW 0.43 mm, with small median antebasal fovea and abrupt basal impression. Elytra wider than long, EL 0.57 mm, EW 0.74 mm, dorsal surface with sparse, short setae, with two pairs of shallow foveae at base. Protrochanters slightly expanded at ventral margin ( Fig. 5 K). Abdomen wider than long, AL 0.58 mm; AW 0.71 mm, slightly narrowed at base; tergite IV (first visible tergite) sparsely pubescent, with narrow basal sulcus; discal carinae relative long, relatively close, extending to one-third of tergal length, width between discal carinae 0.25 mm at apices; short marginal carinae extending to apical one-third of tergal length. Aedeagus ( Fig. 8 A–C) 0.35 mm in length, relatively stout, parameres shorter than median lobe, each with two short, preapical setae; endophallus with two asymmetric sclerites, with numerous weakly sclerotized spine-like structures laterally.

Female. Very similar to male in general appearance; protrochanters simple; each eye composed of about 20 facets. Measurements: BL 1.90 mm; HL 0.43 mm; HW 0.42 mm; PL 0.35 mm; PW 0.43 mm; EL 0.55 mm; EW 0.74 mm; AL 0.57 mm; AW 0.71 mm; width between discal carinae of tergite IV 0.25 mm at apices.

Comparative notes. Batraxis hainanensis is close to B. spinosas by sharing the abrupt subantennal transverse sulcus, and slightly elongate antennomeres III–IX. These two species can be separated by the distinct small median antebasal fovea and abrupt basal sulcus on the pronotum, more widely separated discal carinae of tergite IV, simple pro- and mesotibiae, and aedeagus with shorter parameres and asymmetric endophallus in B. hainanensis . In B. spinosas the pronotal median antebasal fovea is reduced to a depressed area, the protibiae and mesotibiae are apically spinose, the discal carinae of tergite IV are closer, and the aedeagus has much longer parameres and symmetric endophallus.

Distribution. Southern China: Hainan.

Etymology. The specific epithet is taken after the island where the type locality lies, i.e. Hainan.

Figures

FIGURE 3. Dorsal habitus of Batraxis species. A. B. hainanensis. B. B. minor. 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 8. Aedeagi of Batraxis species. (A, D. in dorsal view. B, E. in lateral view. C, F. in ventral view). A – C. B. hainanensis. D – F. B. minor. Scale line: 0.1 mm.