Gracilenta, Zhang & Meng & Beaver, 2022

Zhang, Yi-Feng, Meng, Ling-Zeng & Beaver, Roger A., 2022, A review of the non-lyctine powder-post beetles of Yunnan (China) with a new genus and new species (Coleoptera: Bostrichidae), Zootaxa 5091 (4), pp. 501-545 : 530-531

Gracilenta gen.nov.

Type species: Gracilenta yingjiangensis sp. nov., here designated.

Diagnosis. A member of the tribe Xyloperthini , characterized by the lamelliform intercoxal process of the first abdominal ventrite, the mandibles crossed at the tips, and the well-developed elongate antennal club ( Lesne 1921; Fisher 1950). It is distinguished from other genera of Xyloperthini by the following combination of characters. Frons slightly convex, with a tuft of long, erect, upwardly directed hairlike setae on each side next to inner margin of eyes. Mandibles symmetrical, pointed at tip, with a small tuft of long, erect hairs at basal margin. Antenna with ten antennomeres, the first antennomere of the antennal club rectangular, the second and third distinctly narrower and elongate, gracile, last antennomere 3–4 × as long as wide, the whole club matt, without clear sensory impression areas or erect hairs. Pronotum without a lateral carina, posterior angle of prothorax broadly rounded. Posterior part of elytral disc with three pairs of costae, the first and second not distinct, the third ending in a small process at the upper margin of the elytral declivity. Protibiae normal, widest apically, with a row of sparse, small teeth on posterior face. Last abdominal ventrite segment of male with pleural pieces.

Description. Male. Body cylindrical, elongate.

Head. Deeply inserted in prothorax, not visible from above. Frontoclypeal suture distinct, with median fovea. Frons with a tuft of long, erect, upwardly directed hairlike setae next to inner margin of eyes. Labrum transverse with a fringe of hairs along anterior margin. Epistoma slightly emarginate anteriorly. Mandibles symmetrical, bluntly pointed, with a small tuft of long, erect, and upwardly directed setae at basal margin. Eyes large, weakly oval, globose, strongly projecting. Antenna with 10 antennomeres, first antennomere elongate, antennomeres 3–7 together equal in length to the first, all antennomeres of the antennal club very elongate, the second and third distinctly narrower than the first, the last antennomere about 3.5 × as long as wide, club matt, without depressions or distinct sensory areas or dense erect setae, a few sparse setae on the antennomere lateral margins.

Pronotum. Wider than long, widest in posterior third, a distinct upwardly-directed uncinate tooth on each anterolateral angle, a series of upwardly-directed teeth behind this form lateral border of rasp on anterior half of pronotum, teeth gradually smaller and less erect towards summit of pronotum, pronotal disc slightly coarsely punctured, matt, postero-lateral angles broadly rounded, vestiture of short to moderately long hair-like setae.

Elytra. Parallel-sided, slightly widened posteriorly, about twice as long as pronotum, discal punctures gradually increasing in size posteriorly, strongest on upper part of declivity; declivity angularly separated from disc, steep, lateral margin with a pair of tubercles located at the mid-height of the declivity, elytral margin sharp, separated by a marginal groove from lateral parts of elytra, thickened and forming a broad false epipleuron apically.

Abdomen. Male with pleural pieces, without modifications of the abdominal ventrites. Female unknown.

Relationships. The lamelliform intercoxal process of the first abdominal ventrite, the mandibles crossed at the tips and the well-developed elongate antennal club show that Gracilenta gen.nov. clearly belongs in the tribe Xyloperthini ( Lesne 1901; Fisher 1950). Gracilenta appears most similar to Xylodrypta and Xylodectes among the Xyloperthine genera distributed in the Oriental region. However, it is distinguished from both genera by the large size (10 mm long), very elongate antenna with the last antennomere about 3.5 × as long as wide, and the presence of tufts of hairs on the frons only next to the eyes. It is further distinguished from Xylodrypta by the presence of a false epipleuron near the apex of the elytra, and pleural pieces present in the male.

Distribution. Known only from S-W China (Yunnan).

Etymology. The genus name is feminine, and refers to the gracile, elongated antenna club. Latin gracilis means slender.