Lathrobium abruptum, Assing, 2014

Assing, Volker, 2014, New species and records of Lathrobium from the Palaearctic region, primarily from Nepal (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (1), pp. 1-28 : 14

Lathrobium abruptum sp. n.

( Figs 62–69 , Map 1 )

Type material: Holotype : “ NEPAL Prov. Bheri, Distr. Surkhet , 20 km N Surkhet 2000 m 01.VI.1995 leg. A. Weigel / Holotypus  Lathrobium abruptum sp. n., det. V. Assing 2013” ( NME).

Paratypes: 2 : same data as holotype ( NME, cAss) .

Etymology: The specific epithet (Latin, adjective) refers to the abruptly narrowed ventral process (ventral view).

Description: Body length 4.7–5.5 mm; length of forebody 2.4 mm. Habitus as in Fig. 62 . Coloration: forebody reddish to dark-reddish; abdomen reddish to darkbrown; legs and antennae reddish.

Head ( Fig. 63 ) approximately 1.1 times as long as broad; punctation sparse and moderately coarse; interstices on average distinctly broader than diameter of punctures, with shallow microreticulation. Eyes small, composed of approximately 10 ommatidia, approximately one-fifth as long as postocular region in dorsal view. Antenna approximately 1.3 mm long.

Pronotum ( Fig. 63 ) slender, 1.22–1.30 times as long as broad and about as broad as head or slightly broader; punctation similar to that of head; midline broadly impunctate; interstices without microsculpture.

Elytra ( Fig. 63 ) rather broad and approximately 0.6 times as long as pronotum; punctation fine and sparse; interstices without distinct microsculpture. Hind wings completely reduced. Protarsomeres I–IV with weakly pronounced sexual dimorphism.

Abdomen only slightly broader than elytra; punctation rather coarse and not very dense; interstices with shallow microsculpture; posterior margin of tergite VII without palisade fringe.

: protarsomeres I–IV moderately dilated; posterior margin of tergite VIII convex; sternite VII ( Fig. 64 ) distinctly transverse, posterior margin rather shallowly concave in the middle, margin of this concavity with comb of approximately 25 long pectinate setae, anterior to this comb with rather sparse long black setae; sternite VIII ( Fig. 65 ) weakly transverse, in the middle with extremely short, fine, and sparse pubescence, posterior excision rather deep and somewhat asymmetric; aedeagus ( Figs 66–67 ) 1.1 mm long and nearly symmetric; ventral process basally broad and apically extending into a long and extremely fine, acute spine; dorsal plate broad and short, in lateral view curved; internal sac with dark membranous structures.

: protarsomeres I–IV moderately dilated, slightly less so than in male; tergite VIII of similar shape as in male; sternite VIII ( Fig. 68 ) approximately 1.1 times as long as broad, sparsely pubescent, posterior margin obtusely angled in the middle; tergite IX ( Fig. 69 ) undivided in the middle, postero-lateral processes short, only slightly extending beyond apex of tergite X; tergite X ( Fig. 69 ) flat, of oval shape, and approximately as long as anteromedian portion of tergite IX.

Comparative notes: Based on the male sexual characters (chaetotaxy of the male sternite VII; shape of the male sternite VIII; sting-shaped ventral process of the aedeagus), L. abruptum undoubtedly belongs to the L. pectinatum group. It differs from other representatives of this group particularly by the shape and chaetotaxy of the male sternite VII and by the structure of the aedeagus.

Distribution and natural history: The type locality is situated in Surkhet District, Bheri Province, West Nepal ( Map 1 ), at an altitude of 2000 m.

Figures

Map 1: Distributions of Lathrobium species in Nepal: L. semicirculatum (white triangles), L. constrictum (black triangle), L. descendens (white circles), L. ascendens (black circle), L. rude (white star), L. latibasale (black star), L. eques (white diamond), L. equitans (black diamond), L. abruptum (black square), L. kemum (white square).

Figs 62–78: Lathrobium abruptum sp. n. (62–69) and L. kemum sp. n. (70–78): male habitus (62, 70); forebody (63, 71); male sternite VII (64, 73); male sternite VIII (65, 74); aedeagus in lateral and in ventral view (66–67, 75–76); female sternite VIII (68); female tergites IX–X (69, 78); metatibia (72); dorsal plate of aedeagus in dorsal view (77). Scale bars: 62–63, 70–71: 1.0 mm; 64–69, 72–76, 78: 0.5 mm; 77: 0.2 mm.