Micrillus distortus, Assing, 2013

Assing, V., 2013, On the Palaearctic and Oriental species of Scymbalium and Micrillus (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 45 (2), pp. 1479-1520 : 1504-1507

Micrillus distortus nov.sp.

( Figs 36-43 , Map 4 )

Type material examined Holotype: " Laos: Khammouane prov., Ban Khounkham ( Nahin ), 17-18.vi. 2008, 300 m, 18°13.027'N 104°30.880'E / A. Solodovnikov & J. Pedersen leg. Disturbed primary rain forest; ZMUC collection / Holotypus Micrillus distortus sp.n., det. V. Assing 2012" ( ZMUC) . Paratypes: 1, 5: same data as holotype ( ZMUC, cAss) ; 1: " Laos -C, Kham Mouan pr., Ban Khoun Ngeun , ç 200 m, 18°07'N 104°29'E, Pacholátko leg., 24.-29.iv.2001 " ( NHMB) ; 1: " Saigon, Indo-China / M. Cameron. Bequest. B.M. 1955-147." ( BMNH) ; 1: "T-Thailand, Chiang.M., NW Chiang Mai, Pai City, 29.4.1993, Pacholatko & Dembicky" ( NHMW) .

Etymology: The specific epithet (Latin, adjective: distorted) refers to the distinctly asymmetric aedeagus.

Description: Small species; body length 3.8-4.7 mm; length of forebody: 2.0- 2.3 mm. Habitus as in Fig. 36 . Coloration: head reddish-brown to dark-brown; remainder of body reddish; legs reddish-yellow; antennae reddish.

Head ( Fig. 37 ) approximately as long as broad; punctation composed of sparse micropunctation and few interspersed macropunctures; interstices with very shallow microsculpture and glossy. Eyes 0.6-0.8 times as long as postocular region and weakly projecting from lateral contours of head in dorsal view. Apical joint of maxillary palpus of conical shape and distinctly less than half the length of preapical joint.

Pronotum ( Fig. 37 ) approximately 1.1 times as long as broad and almost as broad as head, noticeably tapering posteriad; surface glossy and with extremely fine, barely noticeable micropunctation; on either side of midline with series of few (4-5) larger punctures.

Elytra ( Fig. 37 ) approximately as long as pronotum; punctation dense and distinct. Hind wing fully developed. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen slightly narrower than elytra; punctation rather dense, fine, but distinct; interstices with very shallow microsculpture; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII strongly convex.

: sternite VII ( Fig. 38 ) moderately transverse, posterior margin concave in the middle, pubescence unmodified; sternite VIII ( Fig. 39 ) oblong, with deep and very narrow posterior excision; aedeagus 0.40-0.45 mm long, strongly asymmetric, and of distinctive shape; internal sac with long and asymmetric sclerotized structure.

Comparative notes: This species is characterized by the distinctive morphology of the aedeagus and additionally distinguished from M. indicus , M. nigriceps , and M. flavescens by different head shape (flattened, posteriorly not tapering, not oblong) and the almost obsolete microsculpture of the head, from M. indicus and M. nigriceps also by shorter antennae with less oblong preapical antennomeres, and from M. asperiventris by the less convex, posteriorly distinctly tapering pronotum with much sparser and finer punctation, the longer and more slender antennae (preapical antennomeres not distinctly transverse), and the denser punctation of the abdomen.

Distribution and natural history: Micrillus distortus was discovered in two localities in Khammouane province in central Laos, one in Vietnam, and one in northern Thailand ( Map 4 ). The specimens from the type locality were collected in a degraded primary forest.

Figures

Map 4: Distributions of Micrillus distortus nov.sp. (triangles) and M. suturalis (CAMERON) (circles) in the Oriental region, based on examined records.

Figs 36-43: Micrillus distortus nov.sp.: (36) habitus; (37) forebody; (38) male sternite VII; (39) male sternite VIII; (40-41) aedeagus in lateral and in ventral view; (42) ventral process of aedeagus in ventral view; (43) internal structure of aedeagus in dorsal view. Scale bars: 36-37: 1.0 mm; 38- 43: 0.2 mm.