Ancystrocerus lueliangi, Yin, 2020

Yin, Zi-Wei, 2020, Two new species of Ancystrocerus Raffray from the Oriental region (Coleoptera, Staphylinidae, Pselaphinae), ZooKeys 958, pp. 29-34 : 29

Ancystrocerus lueliangi sp. nov. Fig. 1

Type material.

Holotype: China: ♂, 'China: Yunnan, Yingjiang Co. (盈江县), Tongbiguan N. R. (铜壁关自然保护区), 24.6136444N, 97.5851155E, 1255 m, 28.viii.2019, Liang Lü leg.' (SNUC).

Diagnosis.

Male. Length 2.4 mm (combined length of head, pronotum, elytra and abdomen). Head and pronotum roughly punctate. Antennomeres 4 and 5 subequal in length, 9 and 10 expanded laterally, apex of antennomeres 9 and base of antennomeres 10 obliquely constricted, each with one bunch of bristles. Pronotum with small, conical discal spine. Tergites 1 and 2 (IV and V) with median carina extending through entire tergal length. Aedeagus relatively more slender, median lobe symmetrical in dorso-ventral view; endophallus with single long sclerite and two pairs of short sclerites; parameres each elongate and with two long apical setae.

Description.

Male (Fig. 1A ). Length 2.4 mm. Head (Fig. 1B ) slightly longer than wide, length from anterior margin of clypeus to posterior margin of vertex (excluding occipital construction) 0.51 mm, width across eyes 0.43 mm; dorsal surface roughly punctate; postocular margins with dense tufted hairs; eyes prominent, each composed of about 35 facets. Antennae (Fig. 1C ) elongate, with clubs (Fig. 1D ) formed by apical three antennomeres; scapes large, antennomeres 2 smaller than scapes, antennomeres 3-8 each subquadrate, 8 slightly transverse and larger than each of antennomeres 2-7, antennomeres 9-10 modified, antennomeres 11 largest, elongate, widest at middle. Pronotum (Fig. 1B ) slightly longer than wide, length along midline 0.56 mm, maximum width 0.52 mm, roughly punctate, disc with small, acute denticle at middle. Elytra much wider than long, length along suture 0.66 mm, maximum width 0.87 mm; shallow and broad discal striae extending posteriorly to past half of elytral length. Legs simple, elongate. Abdomen wider than long, length along midline 0.66 mm, maximum width 0.87 mm. Tergite 1 (IV) approximately as long as tergite 2 (V), both tergites with entire and distinct median carina. Length of aedeagus (Fig. 1E, F ) 0.47 mm, elongate, well sclerotized; median lobe curved ventrally at apex in lateral view; endophallus composed of one elongate sclerite at middle and two short and strongly sclerotized sclerites at apex; parameres elongate and flattened, each with two long setae at apex.

Female. Unknown.

Comparative notes.

Males of the new species can be readily separated from A. chinensis and all other congeners by the roughly punctate head and pronotum, and the different shape of antennomeres 9-10 and structure of the aedeagus. Ancystrocerus chinensis from Hainan has finely punctate head and pronotum, the antennomeres 9 and 10 more elongate, and aedeagus much more robust and with a large projection at the apex of the median lobe.

Distribution.

China: Yunnan.

Biology.

The single male was sifted from a leaf litter sample in a shady broad-leaved forest.

Etymology.

The new species is named after Liang Lü, collector of the holotype.

Figures

Figure 1. Ancystrocerus lueliangi sp. nov., male A habitus B head dorsum and pronotum C right antenna D antennal club of right antenna E, F aedeagus in ventral (E) and lateral (F) view. Scale bars: 1.0 mm (A); 0.3 mm (B, D); 0.5 mm (C); 0.2 mm (E, F).