Lathrobium abruptum, Assing, 2015

Assing, Volker, 2015, New species and additional records of Lathrobium and Elytrobium from the Palaearctic region, with special reference to the fauna of East Yunnan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 65 (1), pp. 41-74 : 62-64

Lathrobium abruptum spec. nov.

( Figs 93–101 )

Type material: Holotype : “P. R. CHINA, Sichuan, NE slope Gongga Shan, N 29°47'49" E 102°03'46", 14.vi.2011, 2684 m, sift18, V. Grebennikov / Holotypus  Lathrobium abruptum spec. nov., det. V . Assing 2014” ( CAS).

Paratypes: 3 , 1 : same data as holotype; 3 , 3 : “P. R. CHINA, Sichuan, NE slope Gongga Shan, N 29°48'15" E 102°03'44", 20.vi.2011, 2765 m, sift22, V. Grebennikov”; 1 , 1 : same data, but “ 6.VI.2011, ..., sift11” (paratypes in CAS, cSme, cAss) .

Etymology: The specific epithet (Latin, adjective) alludes to the abruptly angled ventral process of the aedeagus (lateral view).

Description: Species of moderately large size and with weakly pronounced sexual size dimorphism; body length 9.7–10.8 mm (), 9.0– 10.2 mm (); length of forebody 4.1–4.6 mm (), 3.8–4.2 mm (). Coloration: body blackish-brown to black, with the elytra sometimes slightly paler; legs dark-reddish to reddish-brown, with the profemora mostly darker (blackish-brown); antennae dark-reddish.

Head ( Fig. 93 ) 1.00–1.04 times as broad as long, widest behind eyes; punctation not very coarse, moderately dense in lateral and posterior dorsal portions, sparser in median dorsal portion; interstices with distinct microreticulation. Eyes flat, not projecting from lateral contours of head, and small, approximately one-fourth as long as postocular region in dorsal view, composed of somewhat more than 50 ommatidia. Antenna 2.2–2.4 mm long.

Pronotum ( Fig. 93 ) moderately slender, 1.25–1.30 times as long as broad and 1.01–1.04 times as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 93 ) 0.55–0.59 times as long as pronotum, not distinctly dilated posteriad; humeral angles moderately marked; punctation conspicuously fine and sparse; interstices without microsculpture. Hind wings completely reduced.

Abdomen approximately 1.05–1.10 times as broad as elytra; punctation fine and dense on tergites III–VII, only slightly less dense on tergite VIII; interstices with fine microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII without sexual dimorphism, posterior margin weakly convex.

: protarsomeres I–IV strongly dilated; sternite VII ( Fig. 94 ) strongly transverse, approximately 1.6 times as broad as long, with moderately pronounced posteromedian impression of triangular shape, this impression with a cluster of modified stout black setae, posterior margin broadly concave, in the middle somewhat more distinctly concave; sternite VIII ( Fig. 95 ) distinctly transverse, approximately 1.2 times as broad as long, shallowly impressed and with dense weakly modified setae in postero-median portion, posterior excision not very deep and broadly V-shaped; aedeagus ( Figs 96–99 ) approximately 2.0 mm long and slender, not distinctly asymmetric in ventral view; ventral process very long, slender, and apically acute, abruptly angled at apical third in lateral view; dorsal plate with strongly scle- rotized, long, strongly curved (lateral view) and apically acute apical portion and with short, weakly sclerotized, lamellate basal portion; internal sac with pair of long and weakly sclerotized structures.

: protarsomeres I–IV dilated, but distinctly less so than in male; sternite VIII ( Fig. 100 ) approximately 1.4 mm long and 1.15 times as long as broad, posterior margin convexly projecting in the middle; tergite IX ( Fig. 101 ) with long and undivided median portion and with slender postero-lateral processes; tergite X ( Fig. 101 ) long and slender, approximately 1.3 times as long as anteromedian portion.

Comparative notes: Based on the similar modifications of the male and female sexual characters, this species is undoubtedly most closely related to L. hailuogouense , which too is endemic to the Gongga Shan. It differs from this species only by the more extensive and more distinct postero-median cluster of modified setae on the male sternite VII and by the morphology of the aedeagus ( L. hailuogouense : ventral process less strongly narrowed and less strongly angled at apical third, apex of ventral process shorter and less slender; apical portion of dorsal plate curved in apical half, in L. abruptum in basal half, in lateral view). For illustrations of L. hailuogouense see PENG et al. (2012).

Distribution and natural history: The type material was collected by sifting forest litter in the northeastern Gongga Shan at altitudes of approximately 2680 and 2760 m.

Figures

Figs 93–101: Lathrobium abruptum spec. nov.: forebody (93); male sternite VII (94); male sternite VIII (95); aedeagus in lateral view (96); aedeagus in dry preparation in lateral, ventral, and dorsal view (97–99); female sternite VIII (100); female tergites IX–X (101). Scale bars: 93: 1.0 mm; 94–101: 0.5 mm.