Elytrobium edentulum, 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 : 72-73

Elytrobium edentulum spec. nov.

( Figs 143–149 )

Type material: Holotype  [antennomeres X–XI of left antenna and antennomere XI of right antenna missing]: “P. R. CHINA, Shaanxi, N slope Qin Ling Shan, N34°01'07", E107°51'50", 17.v.2011, 1700–2200 m, sift02, V. Grebennikov / Holotypus  Elytrobium edentulum spec. nov., det. V. Assing 2014” ( CAS).

Etymology: The specific epithet (Latin, adjective: without tooth) alludes to the apically smoothly convex ventral process of the aedeagus, one of the characters distinguishing this species from the sympatric E. qinlinganum ASSING, 2013 .

Description: Body length 7.3 mm; length of forebody 3.7 mm. Coloration: body black; legs with dark-brown femora, brown tibiae, and yellowish to pale-brown tarsi; antennae reddish with slightly darker antennomere I.

Head ( Fig. 144 ) 1.13 times as long as broad, broadest across eyes, and distinctly tapering behind eyes; posterior angles broadly rounded, indistinct; postero-median dorsal portion somewhat elevated; punctation coarse and dense, slightly sparser in median dorsal portion; interstices narrower than diameter of punctures (except in median dorsal portion), with distinct microreticulation, and subdued shine ( Fig. 145 ). Eyes moderately large, nearly half as long as postocular region from posterior margin of eye to neck in dorsal view. Antennomeres IV–X weakly oblong. Maxillary palpi with palpomere III slender, approximately 3.5 times as long as broad.

Pronotum ( Fig. 144 ) 1.2 times as long as broad and 1.13 times as broad as head, broadest in posterior half, distinctly tapering anteriad; lateral margins nearly straight in dorsal view; punctation similar to that of head; interstices without microreticulation along midline, with very shallow microreticulation laterally; impunctate median band narrow, not reaching posterior margin.

Elytra ( Fig. 143 ) long and large, 1.05 times as long and more than 1.5 times as broad as pronotum; punctation dense, distinct, coarser than that of pronotum, and not distinctly seriate; interstices without microreticulation, glossy. Protarsomeres I–IV strongly dilated. Metatarsomere I shorter than II.

Abdomen distinctly narrower than elytra, segments III–VI of subequal width; punctation dense and rather coarse on anterior tergites, gradually becoming finer and sparser towards abdominal apex; interstices with shallow microreticulation; posterior margin of tergite VII with palisade fringe.

: sternite VII unmodified; sternite VIII ( Fig. 146 ) distinctly oblong, 1.1 times as long as broad, posterior excision shallow and with noticeable angle in the middle, pubescence unmodified; aedeagus ( Figs 147–148 ) small in relation to body size, 0.7 mm long; dorsal plate short and apically acute ( Fig. 149 ); internal sac with plateshaped internal structure ( Fig. 149 ).

Comparative notes: Using the key in ASSING (2013e), E. edentulum would key out at couplet 3, together with E. qinlinganum ASSING, 2013 , from which it differs by the elevated postero-median dorsal portion of the head, the slightly more oblong antennomeres IV–X, the different shape of the pronotum ( E. qinlinganum : lateral margin nearly parallel in dorsal view), the presence of shallow microsculpture on the pronotum, the less strongly dilated protarsomeres I–IV, and the distinctly smaller and differently shaped aedeagus. For illustrations of E. qinlinganum and other species of the genus see ASSING (2013e).

Distribution and natural history: The type locality is situated in the Qinling Shan in southern Shaanxi.The holotype was sifted at an altitude between 1700 and 2200 m.

Figures

Figs 143–149: Elytrobium edentulum spec. nov.: forebody (143); head and pronotum (144); median dorsal portion of head (145); male sternite VIII (146); aedeagus in lateral and in ventral view (147–148); apical portion of aedeagus in dorsal view (149). Scale bars: 143–144: 1.0 mm; 146: 0.5 mm; 145, 147–149: 0.2 mm.