Ancystrocerus chinensis, Yin, Zi-Wei, Wang, Dan & Li, Li-Zhen, 2015

Yin, Zi-Wei, Wang, Dan & Li, Li-Zhen, 2015, Discovery of the genus Ancystrocerus Raffray in China, with description of a new species (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 3949 (4), pp. 584-588 : 585-588

Ancystrocerus chinensis , new species

Type material (5 ♂♂, 6 ♀♀). Holotype ( SNUC): 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 with termites, 995 m, 23.i.2015, Peng, Song, Yin, Zhou leg. Paratypes ( SNUC): CHINA: 1 ♂, 5 ♀♀, same data as holotype; 2 ♂♂, 1 ♀, same locality, except ‘ 27.i.2015 ’; 1 ♂, labeled ‘ China: Hainan, Qiongzhong Hsien [¼ φθ], Limu Mt.. Γ ϔDzM ∃, path to Limu Temple, 19°08'57"N, 109°45'39"E, creek valley, decaying log with termites, ca. 635 m, Yan & Yin leg.’.

Diagnosis. Male. Length 2.49–2.63 mm. Antennomeres III–VII about as long as wide, VIII slightly large than VII, IX–X expanded laterally, apex of IX and base of X obliquely emarginate, each with a bunch of bristles. Pronotum with a small, conical discal spine. Tergite IV (first visible tergite) with short median carina extending to one-third of tergal length. Aedeagus nearly symmetric in dorso-ventral view, stout, endophallus with single long sclerite, parameres flattened.

Description. Male ( Fig. 1 A). Length 2.51–2.63 mm. Head slightly longer than wide, HL 0.50–0.53 mm, HW 0.47–0.48 mm, postocular margins with dense tufted hairs; eyes relatively large, each composed of about 60 facets.

Maxillary palpi as in Fig. 2 D. Antennae ( Fig. 2 A) with clubs formed by apical three antennomeres; scapes large, antennomeres II smaller than scapes, III slightly shorter than II, II–VII subequal in width, VIII slightly larger than VII, IX–X ( Fig. 2 B) modified, XI largest, elongate, widest at apical third. Pronotum slightly longer than wide, PL 0.54–0.60 mm, PW 0.53–0.55 mm, disc with small spine ( Fig. 2 C). Elytra wider than long, EL 0.71–0.72 mm, EW 1.00– 1.07 mm; discal stria shallow, extending to half elytral length. Legs simple, elongate. Abdomen wider than long, AL 0.76–0.78 mm, AW 0.96–1.00. Tergite IV longer than V, lacking discal carinae, with short median carina. Sternite IX ( Fig. 2 E) composed of paired membranous sclerites. Length of aedeagus ( Fig. 2 F–H) 0.32 mm, stout, well sclerotized; median lobe curved ventrally in lateral view, endophallus composed of single elongate sclerite, parameres flattened, each with three long apical setae.

Female ( Fig. 1 B). General habitus similar to male; antennae lacking modification; each eye composed of about 60 facets. Measurements: BL 2.49–2.57 mm; HL 0.53–0.54 mm; HW 0.45–0.48 mm; PL 0.50–0.55 mm; PW 0.52– 0.54 mm; EL 0.72–0.73 mm; EW 0.95–1.00 mm; AL 0.73–0.76 mm; AW 0.93–0.98 mm.

Comparative notes. The new species can be readily separated from all congeners, except for A. longicornis which was known from a single female, by the form of the antennal modifications, combined with its relatively large size (2.49–2.63 mm) and form of the aedeagus. The male of Ancystrocerus chinensis shares with A. punctatus a similar form of the antennal modification. These two species can be separated by the antennomeres IX much more strongly protruding at the apicolateral margins, the bristles on antennomeres IX longer than those on antennomeres X, and the aedeagal endophallus composed of two elongate sclerites in A. punctatus .

Biology. All individuals of the new species were collected from inside decomposing logs, frequently in the company of termite colonies, but the association of the new species with termites cannot be confirmed at this moment.

Distribution. Southern China: Hainan.

Etymology. The specific name refers to China where the new species was found.

Figures

FIGURE 1. Dorsal habitus of Ancystrocerus chinensis. A. Male. B. Female. Scales: 1.0 mm.

FIGURE 2. Diagnostic features of male Ancystrocerus chinensis. A. Right antenna. B. Antennal club, enlarged. C. Head and prothorax, in lateral view (arrow indicates the pronotal discal spine). D. Left maxillary palpus. E. Sternite IX. F. Aedeagus, in dorsal view. G. Same, in lateral view. H. Same, in ventral view. Scales: A, C = 0.5 mm; B = 0.3 mm; D, E = 0.1 mm; F, G, H = 0.2 mm.