Lathrobium jiajinum, Assing, 2016

Assing, Volker, 2016, Six new species, a new name, and additional records of Lathrobium from the Palaearctic region (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 48 (1), pp. 191-210 : 204-207

Lathrobium jiajinum nov.sp. ( Figs 30-38 )

T y p e m a t e r i a l: Holotype 3: " CHINA: Sichuan Prov., 37 km N Baoxing, Qiao Qi vill., Jiajin Shan Nat. Forest Park, 15.VI.2014, 2800 m, 30°40'46''N, 102°41'47''E, / sift #21, mixed forest, with Acer, Picea, Betula, broadleaved trees, sifted rotten wood and around fallen trunks, J. Hájek & J. Růžička leg. / Holotypus 3 Lathrobium jiajinum nov.sp., det. V. Assing 2016" (NMP). Paratypes: 13, 2♀♀: same data as holotype (NMP, cAss).

E t y m o l o g y: The specific epithet is an adjective derived from the name of the mountain where the type locality is situated.

D e s c r i p t i o n: Body size subject to distinct sexual dimorphism: body length 6.5- 7.2 mm (3), 5.7-6.3 mm (♀); length of forebody 3.3-3.4 mm (3), 3.0 mm (♀). Coloration: body blackish-brown to black, with the posterior margin of the elytra and the posterior margins of the posterior abdominal segments paler; legs and antennae reddish to reddish-brown.

Head ( Fig. 30 ) approximately as long as broad, more or less distinctly dilated posteriorly; punctation moderately coarse and moderately dense, less dense and less coarse in median dorsal portion; interstices with shallow microreticulation. Eyes moderately small, little more than one-fourth as long as postocular region in dorsal view, and composed of approximately 50-60 ommatidia. Antenna 1.5-1.9 mm long.

Pronotum ( Fig. 30 ?) approximately 1.3 times as long as broad and 1.05-1.10 times as broad as head; punctation moderately dense, finer than that of head; interstices without microsculpture; midline broadly impunctate.

Elytra ( Fig. 30 ) approximately 0.55 times as long as pronotum; humeral angles weakly marked; punctation shallow and ill-defined; interstices without microsculpture. Hind wings completely reduced. Protarsomeres I-IV with distinct sexual dimorphism.

Abdomen slightly broader than elytra; punctation distinct and dense, nearly as dense on tergite VII as on anterior tergites; microsculpture nearly obsolete; posterior margin of tergite VII without palisade fringe; posterior margin of tergite VIII weakly convex.

3: protarsomeres I-IV strongly dilated ( Fig. 30 ); sternite VII ( Fig. 31 ) strongly transverse, with postero-median impression, this impression with numerous modified short and stout black setae, posterior margin weakly, but distinctly concave in the middle; sternite VIII ( Fig. 32 ) approximately 1.15 times as broad as long, posterior half of midline narrowly without pubescence, on either side of midline with modified pubescence posteriorly, posterior margin broadly and rather deeply concave; aedeagus ( Figs 33-36 ) approximately 1.25 mm long, slender, and symmetric; ventral process apically bent and hooked; dorsal plate lamellate and weakly sclerotized, basal portion practically obsolete; internal sac with a long weakly sclerotized membranous structure dorsally and with two spine-shaped, more strongly sclerotized, and basally connected structures ventrally.

♀: protarsomeres I-IV dilated, but distinctly less so than in male; sternite VIII ( Fig. 37 ) approximately 1.15 times as long as broad, posterior margin convexly produced in the middle; tergite IX ( Fig. 38 ) undivided in the middle, postero-lateral processes distinctly projecting beyond apex of tergite X; tergite X ( Fig. 38 ) flat in cross-section and slightly longer than antero-median portion of tergite IX.

C o m p a r a t i v e n o t e s: As can be inferred from the morphology of the aedeagus (symmetric, ventral process slender, dorsal plate lamellate, internal sac with two long sclerotized structures) and from the modifications of the male sternite VII and VIII, L. jiajinum belongs to the L. bibaculatum group, which was previously represented in Sichuan by seven species ( ASSING 2013d, f). The new species is distinguished from other species of this group particularly by the distinctive shape of the ventral process of the aedeagus.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The type locality is situated in the Jiajin Shan to the North of Baoxing, some 120 km to the west of Chengdu. The specimens were sifted from leaf litter in a mixed forest at an altitude of 2800 m.

Figures

Figs 30-38: Lathrobium jiajinum nov.sp.: (30) male forebody; (31) male sternite VII; (32) male sternite VIII; (33-36) aedeagus in lateral and in ventral view in transparent light (33-34) and in dry preparation (35-36); (37) female sternite VIII; (38) female abdominal segments IX-X. Scale bars: 30: 1.0 mm; 31-38: 0.5 mm.