Lathrobium unguiferum, 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 : 199-200

Lathrobium unguiferum nov.sp. ( Figs 15-22 )

T y p e m a t e r i a l: Holotype 3: " NEPAL Myagdi distr., S-slope Ruyachaur Duri, 37-3900 m, 25.6.1998, leg. Berndt & Schmidt / Ankauf A. Dobbertin, Rostock, 2001, Museum Dresden / Holotypus 3 Lathrobium unguiferum nov.sp., det. V. Assing 2015 " (SMTD). Paratypes: 3♀♀: same data as holotype (SMTD, cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: carrying claws) alludes to the claw-shaped internal structures of the aedeagus.

D e s c r i p t i o n: Body length 4.8-6.3 mm; length of forebody 2.3-2.8 mm. Coloration: body dark-brown to blackish-brown; legs yellowish-brown to brown; antennae reddish.

Head ( Fig. 15 ) 1.02-1.05 times as broad as long; punctation rather coarse and rather dense, slightly less dense in median dorsal portion; interstices without distinct microsculpture, but shallow traces visible in lateral and in posterior dorsal portions. Eyes ( Fig. 16 ) not projecting from lateral contours of head, small, approximately 0.2 times as long as postocular region in dorsal view, and composed of approximately 30 ommatidia.

Pronotum ( Fig. 15 ) approximately 1.25 times as long as broad and as broad as head; punctation similar to that of head, but slightly less coarse; interstices without microsculpture.

Elytra ( Fig. 15 ) short, approximately 0.55 times as long as pronotum; humeral angles weakly marked; punctation shallow and ill-defined; interstices without microsculpture. Hind wings completely reduced. Metatibia somewhat compressed.

Abdomen broader than elytra; punctation moderately fine and dense; interstices with fine microsculpture composed of transverse meshes; posterior margin of tergite VII without palisade fringe; posterior margin of tergite VIII weakly convex.

3: protarsomeres I-IV strongly dilated ( Fig. 15 ); sternite VII ( Fig. 17 ) strongly transverse, shallowly impressed and with moderately dense modified setae in postero-median portion, posterior margin broadly concave; sternite VIII ( Fig. 18 ) transverse, 1.15 times as broad as long, broadly impressed and with a cluster of variably modified setae along the middle, posterior excision rather pronounced and nearly U-shaped, posterior margin on either side of this excision with small projection; aedeagus ( Figs 18-19 ) 1.1 mm long; ventral process straight and apically acute in lateral view and symmetric in ventral view; dorsal plate with long, strongly sclerotized, and apically weakly hooked apical portion, basal portion reduced to minute rudiment; internal sac with two rather massive, strongly sclerotized, and strongly curved spines, with an additional smaller and weakly curved spine, and with a large dark membranous structure.

♀: protarsomeres I-IV dilated, but somewhat less so than in male; sternite VIII ( Fig. 21 ) approximately 1.1 times as long as broad and convexly produced posteriorly; tergite IX ( Fig. 22 ) undivided in the middle and with rather short postero-lateral processes; tergite X ( Fig. 22 ) weakly convex in cross-section and approximately 1.35 times as long as antero-median portion of tergite IX.

C o m p a r a t i v e n o t e s: Based on the external, as well as on the male and female sexual characters, L. unguiferum belongs to the L. emodense group (see ASSING 2012b), which previously included six species: L. emodense COIFFAIT, 1975 (SW- Annapurna), L. curvum ASSING, 2012 (Dhaulagiri) , L. spinosissimum ASSING, 2012 (Annapurna: Lamjung Himal), L. annapurnense ASSING, 2012 (Annapurna: Lamjung Himal), L. rude ASSING, 2014 (SE-Annapurna), and L. kiruense ASSING, 2015 (SE- Annapurna). The new species is distinguished from all of them by the more transverse male sternite VIII with a deeper U-shaped posterior excision and by the morphology of the aedeagus (shapes of the ventral process, the dorsal plate, and the internal structures). It additionally differs from the externally similar and geographically close L. curvum (female unknown) by the shape and chaetotaxy of the male sternite VII ( L. curvum : median impression deeper, more extensive, and with much more numerous and more strongly modified setae; posterior margin with median concavity), the shape and chaetotaxy of the male sternite VIII ( L. curvum : median impression deeper, more extensive, and with much more numerous and more strongly modified setae; posterior excision much broader and less deep), the symmetric (ventral view), apically less acute, and less abruptly narrowed ventral process of the aedeagus, the apically less strongly hooked dorsal plate, and the number and shapes of the internal structures ( L. curvum : with two similarly shaped strongly curved spines, without additional spine, and without large dark membranous structure). For illustrations of the other species of the L. emodense group see ASSING (2012b, 2014, 2015).

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 southern Dhaulagiri range at 28°33'N, 83°26'E. The specimens were sifted at an altitude of 3700-3900 m.

Figures

Figs 15-22: Lathrobium unguiferum nov.sp.: (15) forebody; (16) head in lateral view; (17) male sternite VII; (18) male sternite VIII; (19-20) aedeagus in lateral and in ventral view; (21) female sternite VIII; (22) female abdominal segments IX-X. Scale bars: 15: 1.0 mm; 16-22: 0.5 mm.