Lithocharis bitriangulata, Assing, 2015

Assing, Volker, 2015, A revison of the Lithocharis species of the Palaearctic, Oriental and Australian regions (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 47 (2), pp. 1133-1178 : 1165

Lithocharis bitriangulata nov.sp.

( Figs 90-94 )

Type material: Holotype ♂: " Sumatra (S), SW coast of Rana lake , 1.-4. June 2001, Bolm lgt., 1200 m / Holotypus ♂ Lithocharis bitriangulata sp. n. det. V. Assing 2013" ( NHMB).

Etymology: The specific epithet (adjective) alludes to the pair of triangular apical internal structures of the aedeagus.

Description: Body length 4.3 mm; length of forebody 2.3 mm. Coloration: head blackish; pronotum dark-reddish; elytra yellowish-brown with indistinctly delimited yellowish margins; abdomen brown, with the margins of the segments yellowish; legs yellowish; antennae reddish.

Head ( Fig. 90 ) transverse, 1.08 times as broad as long, indistinctly dilated behind eyes; punctation dense and fine; interstices without distinct microsculpture. Eyes large, distinctly longer than postocular portion in dorsal view. Antennae 1.45 mm long; preapical antennomeres approximately as long as broad.

Pronotum ( Fig. 90 ) 1.1 times as wide as long and 1.02 times as broad as head; posterior angles rounded, weakly marked; punctation similar to that of head; midline with indistinctly delimited, narrow impunctate band; interstices without microsculpture.

Elytra ( Fig. 90 ) 1.1 times as long as pronotum; punctation very dense and fine; interstices without microsculpture. Hind wings present. Protarsomeres I-IV distinctly dilated. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen narrower than elytra; punctation fine and very dense; interstices with distinct microreticulation; posterior margin of tergite VII with palisade fringe.

♂: sternite VII ( Fig. 91 ) moderately transverse, posterior margin weakly concave in the middle and with comb of approximately 30 moderately long palisade setae; sternite VIII ( Fig. 92 ) transverse, extensively without pubescence in postero-median portion, posterior excision large and broadly V-shaped, near middle of margin of this excision with a few long setae; aedeagus ( Figs 93-94 ) large, 0.92 mm long, with strongly sclerotized internal structures of distinctive shapes; dorso-lateral apophyses curved and rather stout.

Comparative notes: Based on the similar external and male sexual characters, L. bitriangulata is closely related to L. vilis . It is distinguished from this species by the less transverse male sternite VII with a differently shaped posterior margin and with a shorter comb with fewer palisade setae, by the different chaetotaxy of the male sternite VIII, and by the slightly smaller aedeagus with internal structures of different shapes.

Distribution and natural history: Thetypelocalityissituatedin in the south of Sumatra, where the holotype was collected on, or near, the shore of a lake.

Figures

Figs 90-94: Lithocharis bitriangulata nov.sp.: (90) forebody; (91) male sternite VII; (92) male sternite VIII; (93-94) aedeagus in lateral and in ventral view. Scale bars: 90: 1.0 mm; 91-94: 0.2 mm.