Tangius Yin & Li, new genus

Tangius Yin & Li, new genus

Type species: Tangius glabellus Yin & Li, new species, by original designation

Diagnosis. Head slightly elongate, nearly hexagonal; lacking frontal rostrum. Antennae compressed, antennomeres II–X moniliform, lacking modifications. Pronotum lacking sulci or carinae, with shallow median antebasal impression and small lateral antebasal foveae. Elytra with three basal foveae, sutural and discal striae present. Tergite IV longer than V–VII combined.

Description. Body medium-sized (3.2–3.5 mm), reddish brown, mouthparts and tarsi paler.

Head with clypeus visible in dorsal view, arcuate at anterior margin; frons convex medially; antennal tubercles slightly raised; small vertexal foveae devoid of setae, widely separated; postocular margins broadly emarginate mesally; posterior margin of head bisinuate; genae sparsely covered with short thick setae; eyes well-developed, but barely visible in dorsal view, reniform in lateral view; single gular fovea large, lacking gular carina or sulcus; maxillary palpomeres I minute, II pedunculate, III nearly triangular, IV largest, fusiform, slightly broadened at middle; antennae with eleven antennomeres, lacking obvious club and modification.

Pronotum roundly expanded laterally in dorsal view; paranotal carinae present. Prosternum with paired lateral procoxal foveae. Mesoventrite lacking median fovea; lateral foveae deep, horizontal; lateral mesocoxal foveae present. Metaventrite slightly depressed and pubescent medially; lateral metaventral foveae present. Legs slender; metatrochanters spinose ventrally.

Elytra glabrous; sutural striae reaching elytral apex; discal striae hardly reaching elytral mid-length; lacking subhumeral foveae and marginal striae; lateroapical clefts indistinct.

Abdomen slightly wider than elytra, rounded apically; tergite IV largest, with mediobasal foveae close, two pairs of basolateral foveae present, areas around foveae deeply impressed, discal carinae indistinct, ridges laterally of outer pair of basolateral foveae, reaching one-third tergal length; tergites V–VI each with two pairs of basolateral foveae; tergite VII lacking foveae; sternite IV with two shallow mediobasal foveae and two pair of distinct basolateral foveae; sternites V–VI each with two pairs of basolateral foveae; sternite VII lacking foveae.

Aedeagus asymmetric and well sclerotized, female genital complex with symmetric sclerites.

Comparative notes. Tangius is close to Dendrolasiophilus Nomura, 2010 (Nomura 2008, 2010), Maajappia Nomura, 2010 and Songius Yin & Li, 2010, sharing with them a similar general appearance related to myrmecophily. The transverse head, the presence of single basal elytral fovea, the lacking of elytral discal striae, and the shallow basal impression of the tergite IV in Dendrolasiophilus readily separate it from Tangius. Maajappia is different in having the head being almost quadrate, the presence of a U-shaped sulcus that connects the vertexal foveae, the absence of elytral basal fovea and discal striae, and the pubescent and punctate dorsal surface of the head, elytra and abdomen. Songius is very distinct, and can be easily distinguished from Tangius and the other two genera by the trapezoidal pronotum and the tergites IV and V having nearly the same length.

Etymology. The generic name is dedicated to Liang Tang, collector of the type series of the only known species. Gender masculine.