Lathrobium laciniatum, 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 : 54-55

Lathrobium laciniatum spec. nov.

( Figs 45–53 )

Type material: Holotype : “ CHINA [12a] – Yunnan, mt. WNW Wuding , mix. forest, 25°38'45"N, 102°06'55"E, 2390 m, 1.IX.2014, V. Assing / Holotypus  Lathrobium laciniatum spec. nov., det. V. Assing 2014” (cAss).

Paratypes: 11 , 11  [5 , 4  teneral; 1  without abdomen]: same data as holotype (cAss, MNHUB); 4 , 3  [1 , 2  teneral]: same data as holotype, but leg. Schülke (cSch); 3 , 3  [1 , 3  teneral]: “ CHINA [12] – Yunnan, mt. WNW Wuding , mix. forest, 25°38'45"N, 102°06'55"E, 2390 m, 18.VIII.2014, V. Assing” (cAss, MNHUB); 3 , 3  [1 , 1  teneral]: same data, but leg. M. Schülke (cSch) .

Etymology: The specific epithet is an adjective derived from the Latin noun lacinia (lobe) and alludes to the shapes of the two apices of the aedeagus.

Description: Species of moderate size, without evident sexual size dimorphism; body length 6.3–7.8 mm; length of forebody 3.3–3.6 mm. Habitus as in Fig. 45 . Coloration: body black; legs pale-brown, with the profemora dark-brown and with the tarsi yellowish-brown; antennae reddish.

Head ( Fig. 46 ) usually weakly oblong, 1.00–1.07 times as long as broad, not dilated behind eyes; punctation moderately coarse and moderately sparse, sparser in median dorsal portion; interstices with distinct microreticulation, on average slightly broader than diameter of punctures in lateral and posterior dorsal portions. Eyes weakly convex, weakly projecting from lateral contours of head and of moderate size, approximately 0.4 times as long as postocular region in dorsal view and composed of significantly more than 50 ommatidia. Antenna relatively long and slender, approximately 2.0– 2.1 mm long.

Pronotum ( Fig. 46 ) rather broad and moderately oblong, 1.20–1.23 times as long as broad and approximately 1.06– 1.10 times as broad as head; punctation similar that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 46 ) short and broad, approximately 1.75 times as broad (combined width) as long and approximately 0.53 times as long as pronotum, not distinctly dilated posteriad; humeral angles moderately marked; punctation moderately dense, shallower than that of pronotum; interstices without microsculpture. Hind wings completely reduced. Protarsomeres I–IV with weakly pronounced sexual dimorphism.

Abdomen approximately 1.1 times as broad as elytra; punctation fine, rather dense on tergites III–VI, sparser on tergite VII; interstices with shallow transverse microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII without evident sexual dimorphism, posterior margin very indistinctly angled in the middle.

: protarsomeres I–IV moderately dilated; sternite VII ( Fig. 47 ) distinctly transverse, approximately 1.45 times as broad as long, posteriorly without distinct median impression and with very weakly concave posterior margin, pubescence not distinctly modified; sternite VIII ( Fig. 48 ) very weakly oblong, posteriorly with very small and shallow excision and with weakly modified black setae; aedeagus ( Figs 49–51 ) approximately 1.1 mm long, nearly symmetric, dorso-ventrally depressed, weakly sclerotized apically, and with small basal portion; ventral process nearly symmetric, apically deeply bifid, the apices slender, ventrally with one median and two lateral carinae extending from apical incision to basal fourth; dorsal plate weakly sclerotized, very short, truncate basally and convex apically, and without separate basal portion; internal sac with a membranous ring-shaped structure, without additional structures.

: protarsomeres I–IV nearly as dilated as in male; sternite VIII ( Fig. 52 ) approximately 1.15 times as long as broad and with strongly convex posterior margin; tergite IX ( Fig. 53 ) with short antero-median portion with median suture and with slender postero-lateral processes; tergite X ( Fig. 53 ) flattened and very long, nearly ten times as long as antero-median portion of tergite IX.

Comparative notes: Based on the external and sexual characters, particularly on the modifications of the aedeagus, L. laciniatum clearly belongs to the L. tentaculatum group. It is distinguished from other species of this group by the smaller, more symmetric, and differently shaped aedeagus, by the shallower posterior excision of the male sternite VIII, and by the more slender body (head oblong; pronotum more oblong; antennae relatively longer). Based on the similar modifications of the aedeagus (presence of three ventral carinae; apices of ventral process of similar shape), L. laciniatum is most closely allied to L. tricarinatum from the environs of Dongchuan.

Distribution and natural history: The type locality is situated to the west-northwest of Wuding in eastern Yunnan. The specimens were sifted from litter at the margin of a mixed forest with alder, pine, and bushes at an altitude of 2390 m. Numerous paratypes are teneral.

Figures

Figs 36–53: Lathrobium tricarinatum spec. nov. (36–44) and L. laciniatum spec. nov. (45–53): habitus (36, 45); forebody (37, 46); male sternite VII (38, 47); male sternite VIII (39, 48); aedeagus in ventral view (40, 49); aedeagus in dry preparation in ventral view (41, 50); aedeagus in dry preparation in dorsal view (42); female sternite VIII (43, 52); female tergites IX–X (44, 53); apical portion of aedeagus in dorsal view (51). Scale bars: 36–37, 45–46: 1.0 mm; 38–44, 47–50, 52–53: 0.5 mm; 51: 0.2 mm.