Lathrobium calvisulcatum, 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 : 61-62

Lathrobium calvisulcatum spec. nov.

( Figs 88–92 )

Type material: Holotype  [slightly teneral]: “P. R. CHINA, Shaanxi, N slope Qin Ling Shan, N 33°51'40" E 108°59'27"", 15.v.2011, 2000–2600 m, sift01, V. Grebennikov / Holotypus  Lathrobium calvisulcatum spec. nov., det. V. Assing 2014” ( CAS).

Etymology: The specific epithet is an adjective composed of the Latin adjective calvus (bald, bare) and the past participle of the Latin verb sulcare (to furrow). It alludes to the absence of pubescence in the median impressions of the male sternites VII and VIII.

Description: Species of moderate size; body length 7.8 mm; length of forebody 3.7 mm. Coloration: forebody dark-brown; elytra brown; abdomen dark-brown with paler apex; body brown to dark-brown; legs and antennae reddish.

Head ( Fig. 88 ) 1.03 times as long as broad, widest behind eyes; punctation moderately coarse and moderately dense, sparser in median dorsal portion; interstices with shallow, but distinct microreticulation. Eyes flat, not projecting from lateral contours of head, and small, approximately one-fourth as long as postocular region in dorsal view and composed of approximately 50 ommatidia. Antenna 1.8 mm long.

Pronotum ( Fig. 88 ) moderately slender, approximately 1.3 times as long as broad and 1.02 times as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 88 ) 0.55 times as long as pronotum, weakly dilated posteriad; humeral angles moderately marked; punctation shallow and moderately dense; interstices without microsculpture. Hind wings completely reduced. Protarsomeres I–IV with pronounced sexual dimorphism.

Abdomen approximately 1.15 times as broad as elytra; punctation fine and moderately dense, sparser and finer on tergites VII and VIII than on anterior tergites; interstices with distinct transverse microsculpture; posterior margin of tergite VII without palisade fringe.

: protarsomeres I–IV strongly dilated; tergite VIII with weakly convex posterior margin; sternite VII ( Fig. 89 ) strongly transverse, approximately 1.7 times as broad as long, with rather extensive and pronounced median impression, this impression broadly without setae along the middle and postero-laterally with a cluster of weakly modified setae, posterior margin distinctly concave in the middle; sternite VIII ( Fig. 90 ) weakly transverse, approximately 1.05 times as broad as long, with narrow and long median impression, this impression without setae, on either side of this impression with an oblong and rather long cluster of weakly modified dark setae, posterior excision distinct and V-shaped; aedeagus ( Figs 91–92 ) nearly 1.5 mm long and symmetric in ventral view; ventral process smoothly curved, slender, and apically acute in lateral view; dorsal plate with long lamellate apical portion and with distinctly shorter lamellate basal portion; internal sac with membranous structures of characteristic shape in lateral view, the dorsal ones shaped like an inverted comma.

: unknown.

Comparative notes: Like the preceding species, L. calvisulcatum belongs to the L. varisternale group. Among the species of this group, the male sexual characters (chaetotaxy of sternites VII and VIII; morphology of the aedeagus) are most similar to those of L. brevilobatum ASSING, 2013 , from which L. calvisulcatum differs by the more transverse male sternite VII with sparser clusters of less modified setae and without setae in the antero-median portion, by a male sternite VIII with a distinctly deeper posterior excision and with more extensive clusters of modified setae, and by the morphology of the aedeagus (shapes of ventral process, dorsal plate, and internal structures). For illustrations of L. brevilobatum see ASSING (2013a).

Distribution and natural history: The type locality is situated in the Qinling Shan to the south of Xi'an in southern Shaanxi. The slightly teneral holotype was sifted together with L. brevitergale at an altitude between 2000 and 2600 m.

Figures

Figs 79–92: Lathrobium grebennikovi spec. nov.(79–87) and L. cavisulcatum spec. nov. (88–92): forebody (79, 88); male sternite VII (80, 89); male sternite VIII (81, 90); aedeagus in lateral view (82, 91); aedeagus in dry preparation in lateral, ventral, and dorsal view (83–85); female sternite VIII (86); female tergites IX–X (87); aedeagus in ventral view (92). Scale bars: 79, 88: 1.0 mm; 80–87, 89–92: 0.5 mm.