Lathrobium imminutum, Assing, 2013

Assing, Volker, 2013, On the Lathrobium fauna of China III. New species and additional records from various provinces (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 63 (1), pp. 25-52 : 41-42

Lathrobium imminutum sp. n.

( Figs 73-79 )

Type material:

Holotype : “ CHINA: BEIJING distr., Yan Shan, Dongling Mts (1400 m), Xiaolongmen, 15.-16.VI.2001, Hlaváč & Cooter lgt / Holotypus  Lathrobium imminutum sp. n., det. V. Assing 2012” (cAss) . Paratype : same data as holotype (cAss).

Etymology:

The specific epithet is the past participle of the Latin verb imminuere (to reduce) and refers to the small body size.

Description:

Conspicuously small species; body length 4.0- 4.2 mm; length of forebody 2.1-2.2 mm. Coloration: head and pronotum blackish-brown; elytra yellowish to yellowish brown posteriorly and more or less extensively infuscate anteriorly; abdomen blackish; legs and antennae palereddish.

Head ( Fig. 73 ) oblong, nearly 1.1 times as long as broad; punctation moderately coarse and moderately dense, somewhat sparser in median dorsal portion; interstices glossy, with very shallow microreticulation. Eyes relatively large, approximately half as long as postocular region in dorsal view, or nearly so, and composed of approximately 40-50 ommatidia. Antenna 1.2-1.3 mm long.

Pronotum ( Fig. 73 ) slender, approximately 1.3 times as long as broad and about 0.95 times as broad as head; punctation similar to that of head; impunctate midline rather broad; interstices without microsculpture.

Elytra ( Fig. 73 ) long, 0.87-0.95 times as long as pronotum; punctation moderately dense, shallow, and weakly defined. Hind wings apparently fully developed. Protarsi with rather weakly pronounced sexual dimorphism.

Abdomen almost matt due to the very dense and fine punctation; punctation of tergite VII slightly less dense than that of anterior tergites; posterior margin of tergite VII with palisade fringe; tergite VIII with pronounced sexual dimorphism.

: protarsomeres I-IV strongly dilated; posterior margin of tergite VIII weakly convex; sternites III-VI unmodified; sternite VII ( Fig. 74 ) relatively strongly transverse,

posteriorly with shallow median impression, this impression with cluster of rather weakly modified dark setae, posterior margin weakly concave, in the middle weakly convex; sternite VIII ( Fig. 75 ) moderately transverse, symmetric, with cluster of weakly modified dark setae in the middle, and with deep V-shaped posterior excision, depth of this excision approximately two fifths of the length of sternite; aedeagus ( Figs 76-78 ) small, 0.6 mm long, symmetric, and with short, laterally compressed, and somewhat curved ventral process; dorsal plate not noticeable; internal sac with dark clusters of semi-transparent spines.

: protarsomeres I-IV distinctly dilated, slightly less so than in male; posterior margin of tergite VIII ( Fig. 79 ) distinctly pointed in the middle; sternite VIII 0.6 mm long, weakly oblong, and with strongly convex posterior margin; tergite IX with very short median portion and with long and slender postero-lateral processes; tegite X weakly convex in cross-section, nearly four times as long as tergite IX in the middle.

Comparative notes:

This species is readily distinguished from all other Lathrobium species recorded from China by its conspicuously small body size alone. In general appearance it resembles macropterous specimens of the trans-Palaearctic L. longulum GRAVENHORST, 1802 from which it is distinguished by the even slightly smaller body size and by the completely different primary and secondary sexual characters. For illustrations of L. longulum see ASSING (2012a).

Distribution and natural history:

Lathrobium imminutum is currently known only from the Yan Shan in Beijing province, but the long elytra and apparently fully developed hind wings suggest that the species may be more widespread. The type specimens were collected at an altitude of 1400 m, together with the widespread L. wuesthoffi KOCH, 1939 .

Figures

Figs 65-79: Lathrobium jinfoicum sp. n. (65-72) and L. imminutum sp. n. (73-79): habitus (65); forebody (66, 73); male sternite VII (67, 74); male sternite VIII (68, 75); aedeagus in lateral and in ventral view (69-70, 76-77); female sternite VIII (71, 79); female tergites IX-X (72); internal structures of aedeagus in lateral view (78). Scale bars: 65-66, 73: 1.0 mm; 67-72, 74-77, 79: 0.5 mm; 78: 0.2 mm.