Araneibatrus gracilipes Yin and Li

Yin, Zi-Wei, Jiang, Ri-Xin & Steiner, Helmut, 2016, Revision of the genus Araneibatrus (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 4097 (4), pp. 475-494 : 488-491

Araneibatrus gracilipes Yin and Li

( Figs 5 D, 6D, 8D, 9D, 11A–C, 12)

Araneibatrus gracilipes Yin & Li, 2010 (in: Yin, Li & Zhao 2010: 55).

Type material studied. Holotype: male: ‘ China: Guangdong Prov., Nanling N. R. [南岭自然保护区], 6# For. Rd. [六号林道], 24°56′34″N, 113°01′26″E, x.2009, alt. ca. 1400 m, Lei GAO leg.’ ( SNUC).

Revised diagnosis. Body length 2.32 mm. Vertex lacking mediobasal and lateral postantennal carinae; clypeus short, less than one-third of total head length. Pronotum with relatively broad median longitudinal sulcus and with faint antebasal sulci; lacking dorsal carinae, with discal and antebasal tubercles. Elytra lacking discal striae; anterolateral margins not emarginate. Metaventrite with narrow notch at middle of posterior margin. Tergite IV with two mediobasal and four basolateral foveae. Sternite IV with two mediobasal and six basolateral foveae. Male with unmodified antennal club and metaventrite, with simple mesotibia and metatrochanter. Aedeagus with a stout and elongate basal capsule.

Redescription. Male (Yin, Li & Zhao 2010: fig. 1). Length 2.32 mm (erroneously given as 2.73 mm in the original description). Body uniformly reddish-brown, mouth parts, tibiae and tarsi lighter in color.

Head as long as wide, HL 0.48 mm, HW 0.48 mm, finely punctate; vertex lacking median carina and lateral postantennal carinae; clypeus relatively short, slightly more than one-fourth of total head length; antennal club loosely formed by three apical enlarged antennomeres, antennomere XI asymmetrically narrowed at apical half. Pronotum slightly narrower than head, and as long as wide, PL 0.45 mm, PW 0.46 mm; disc finely punctate, with relatively broad median longitudinal sulcus and indistinct transverse antebasal sulcus, lacking dorsal carinae, with small discal and antebasal tubercles. Elytra ( Fig. 5 D) slightly wider than long, EL 0.81 mm, EW 0.93 mm, lacking discal striae, anterolateral margins straight. Mesoventrite ( Fig. 6 D) with lateral foveae separated from median foveae. Metaventrite ( Fig. 6 D) unmodified; posterior margin with narrow notch at middle. All legs lacking spines, protuberances or projections. Tergite IV ( Fig. 8 D) with oblique inner marginal carinae extending to apical twothirds of tergal length; basal impression subdivided into three parts by one pair of mediobasal and two pairs of basolateral foveae. Sternite IV ( Fig. 9 D) with one pair of mediobasal and three pairs of basolateral foveae. Length of aedeagus ( Fig. 11 A–C) 0.52 mm, median lobe with stout, elongate basal bulb and large foramen; elongate median lobe broadest at base; dorsal lobe elongate, composed of two elongate sclerites and broad membrane.

Female. Unknown.

Comparative notes. Araneibatrus gracilipes is the only known leaf litter-dwelling species of the genus. It can be readily separated from all the cavernicolous congeners by the relatively stout body form, presence of discal and antebasal tubercles on the pronotum, simple mesotibiae and metatrochanters in the male, and structures of the aedeagus. One female specimen collected in the Dayaoshan Natural Reserve (24°08’N, 110°14’E, ca. 265 km west of Nanling), exhibits morphological features similar to those of the holotype male ( Figs 2 B, 4D), but with much shorter antennae and legs, and smaller eyes. This specimen is possibly conspecific with the holotype from the type locality, but their association must be confirmed by finding specimens of the opposite sex in both localities.

Collecting environment. The holotype was collected from a leaf litter sample subsequently processed by a Winkler extractor.

Distribution. Southern China: Guangdong ( Fig. 12 ).

Figures

FIGURE 2. Dorsal habitus of Araneibatrus species. A. A. grossepunctatus, male. B. A. cf. gracilipes, female. Scales: 0.5 mm.

FIGURE 5. Right elytron of Araneibatrus species. A. A. callissimus. B. A. cellulanus. C. A. grossepunctatus. D. A. gracilipes. E. A. pubescens. F. A. spinosus. Scales: 0.2 mm.

FIGURE 6. Meso- and metaventrite of Araneibatrus species. A. A. callissimus. B. A. cellulanus. C. A. grossepunctatus. D. A. gracilipes. Scales: 0.2 mm.

FIGURE 8. Tergite IV of Araneibatrus species. A. A. callissimus. B. A. cellulanus. C. A. grossepunctatus. D. A. gracilipes. E. A. pubescens. F. A. spinosus. Scales: 0.2 mm.

FIGURE 9. Sternites III and IV of Araneibatrus species. A. A. callissimus. B. A. cellulanus. C. A. grossepunctatus. D. A. gracilipes. E. A. pubescens. F. A. spinosus. Scales: 0.2 mm.

FIGURE 11. Aedeagus of Araneibatrus species (A, D, G. in ventral view. B, E, H. in lateral view. C, F, I. in dorsal view). A – C. A. gracilipes. D – F. A. pubescens. G – I. A. spinosus. Scales: 0.2 mm.

FIGURE 12. Distribution of Araneibatrus species.