Lathrobium tentaculatum, Assing, 2013

Assing, Volker, 2013, On the Lathrobium fauna of China V. New species and additional records from Yunnan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 63 (1), pp. 53-128 : 102-103

4.2 The L. tentaculatum species group

4.2.1 Lathrobium tentaculatum sp. n.

( Figs 227-235 , Map 6 )

Type material:

Holotype ♂: “ CHINA: Yunnan, Pu’er Pref., Ailao Shan , 37 km NW Jingdong, 24°45'12"N, 100°41'24.5"E, 2300 m, devastated forest remnant, litter & dead wood sifted, 13.IX.2009, leg. M. Schülke [CH09-48] / Holotypus ♂ Lathrobium tentaculatum sp. n. det. V. Assing 2013” (cSch). Paratypes : 1 ♂, 1 ♀ [teneral]: same data as holotype (cAss) .

Etymology:

The specific epithet (adjective: with tentacles) alludes to the apically bifid ventral process of the aedeagus.

Description:

Species of large size and stout habitus ( Fig. 227 ); body length 9.5-11.0 mm; length of forebody 4.5-4.8 mm. Coloration: body black; legs blackish-brown with paler tarsi; antennae dark-reddish to brown.

Head ( Fig. 228 ) large, approximately 1.1 times as broad as long; punctation moderately coarse and rather dense, somewhat sparser in median dorsal portion; interstices with fine and very shallow microreticulation. Eyes relatively large, nearly half as long as postocular region in dorsal view and composed of> 60 ommatidia. Antenna approximately 2.7 mm long.

Pronotum ( Fig. 228 ) short and broad, approximately 1.15 times as long as broad and 1.05 times as broad as head; punctation similar to that of head; interstices without microsculpture and glossy; impunctate midline rather narrow.

Elytra ( Fig. 228 ) approximately 0.55 times as long as pronotum and rather broad; punctation dense and defined. Hind wings completely reduced. Protarsi with moderately pronounced sexual dimorphism.

Abdomen 1.10-1.15 times as broad as elytra; punctation fine and very dense on tergites III-VI, sparser on tergites VII and VIII; interstices with shallow microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII without sexual dimorphism, posterior margin angularly produced in the middle ( Fig. 233 ).

♂: sternites III-VI unmodified; sternite VII ( Fig. 229 ) distinctly transverse, symmetric, with shallow and rather small median impression posteriorly, this impression with cluster of moderately modified black setae, posterior margin distinctly concave in the middle; sternite VIII ( Fig. 230 ) symmetric, near posterior excision with dense, weakly modified black setae, posterior excision very small and shallow; aedeagus ( Figs 231-232 ) 1.9-2.0 mm long, somewhat asymmetric, dorso-ventrally compressed, and with small basal portion; ventral process apically extending into two lamellate and somewhat asymmetric processes; dorsal plate with moderately sclerotized and relatively short apical portion and with short basal portion; internal sac without distinct structures, apart from the usual membranous circular structure.

♀: sternite VIII ( Fig. 234 ) approximately 1.3 mm long, approximately as broad as long, and with strongly convex posterior margin; tergite IX ( Fig. 235 ) with very short antero-median portion, and with moderately long and straight postero-lateral processes, antero-median portion with median suture; tergite X ( Fig. 235 ) flat, more than ten times as long as antero-median portion of tergite IX.

Comparative notes:

Among the Lathrobium species known from Yunnan, L. tentaculatum is readily identified not only based on the male sexual characters, particularly the distinctive morphology of the aedeagus, but also based on external characters (large and broad body; large transverse head with rather large eyes; long antennae; dense and defined punctation of the elytra; posterior margin of tergite VIII angularly produced in the middle). The derived morphology of the aedeagus does not suggest a closer relationship to any other Lathrobium species recorded from Yunnan; only the morphology of the female tergites IX and X suggests that L. tentaculatum may be affiliated to the L. daliense group.

Distribution and natural history:

The type locality is situated in the Ailao Shan, to the northwest of Jingdong ( Map 6 ). The specimens were sifted from leaf litter in a forest remnant at an altitude of 2300 m, together with L. rastellatum . The female paratype is distinctly teneral.

Figures

Map 6: Distribution of the species of the L. celere (open stars), the L. yulongense (open triangles), the L. lijiangense (open circles), the L. tentaculatum (black star), and theL. hirsutum(other filled symbols) (sub-)groups:L. lijiangense (white circles);L. yulongense (white triangles); L. tentaculatum (black star); L. hirsutum (black circles); L. baizuorum (black triangles); L. bidigitulatum (white stars).

Figs 227-235: Lathrobium tentaculatum: habitus (227); forebody (228); male sternite VII (229); male sternite VIII (230); aedeagus in lateral and in ventral view (231-232); female tergite VIII (233); female sternite VIII (234); female tergites IX-X (235). Scale bars: 227-228: 1.0 mm; 229-235: 0.5 mm.