Truncaudum bullatum, Smith & Beaver & Cognato, 2020

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Truncaudum bullatum sp. nov. Fig. 78C, D, F

Type material.

Holotype, female, China: Fujian, Fuzhou, Qishan, Y. Li, 18.iv.2018, ex unknown twig (IZAS).

Diagnosis.

1.9 mm long (n = 1); 2.71 × as long as wide. This species is distinguished by the declivity abruptly truncate, surrounded by a complete costa and margined with a row of variably tubercles; declivital interstriae 1 tumescent; and small size.

This species is strikingly similar to many small Cyclorhipidion species and is distinguished by the characters given for the genus.

Similar species.

Amasa spp., Arixyleborus spp., Cyclorhipidion spp., Pseudowebbia spp., Webbia spp.

Description

(female). 1.9 mm long (n = 1); 2.71 × as long as wide. Head, pronotum, antennae and legs light brown. Elytra bicolored: elytral disc light brown, becoming darker apically, declivital face maroon. Head: epistoma entire, transverse, with a row of hair-like setae. Frons weakly convex to upper level of eyes; surface shagreened, impunctate, alutaceous; granulate just above epistoma. Eyes deeply emarginate just above antennal insertion, upper part smaller than lower part. Submentum narrow, triangular, deeply impressed. Antennal scape regularly thick, as long as club. Pedicel as wide as scape, approximately as long as funicle. Funicle 4-segmented, segment 1 shorter than pedicel. Club approximately circular, obliquely truncate, type 2; segment 1 corneous, transverse on anterior face, occupying basal 2/5, nearly covering posterior face; segment 2 narrow, corneous; segment 1 present on posterior face. Pronotum: 1.2 × as long as wide. In dorsal view long and rounded frontally, type 7, sides parallel in basal 1/2, rounded anteriorly; anterior margin without serrations. In lateral view elongate with disc much longer than anterior slope, type 7, disc flat, summit at apical 1/4. Anterior slope with densely spaced, fine asperities, becoming lower and more strongly transverse towards summit, bearing long, fine, erect hair-like setae. Disc shiny, alutaceous with very dense, fine punctures, glabrous. Lateral margins obliquely costate. Base transverse, posterior angles narrowly rounded. Elytra: 1.35 × as long as wide, 1.1 × as long as pronotum. Scutellum small, linguiform, shiny, flush with elytra, flat. Elytral base transverse, edge oblique, humeral angles rounded, parallel-sided in basal 3/4, then sharply angulate to apex. Disc shiny, densely setose; striae not impressed, punctures fine, shallow, separated by three diameters of a puncture; interstriae flat, finely punctate, punctures as large as those of striae, strongly confused, setose, each bearing a short, semi-erect hair-like seta. Declivity truncate, strongly shagreened, dull, almost glabrous; interstriae impunctate, interstriae 1 laterally broadened from declivital summit to apical 1/3 then narrowed to apex, tumescent, one denticle on apical 1/3; tumescent area sparsely setose, setae short, stout, erect; strial punctures very large, shallow, much larger than on disc, punctures subcontiguous with those of adjacent rows. Posterolateral margin forming a circumdeclivital carina, carina coarsely tuberculate, tubercles increasing in size from base to apex. Legs: procoxae contiguous, prosternal coxal piece inconspicuous. Protibiae slender with evenly rounded outer edge, broadest at apical 1/3; posterior face smooth; apical 1/3 of outer margin with four large socketed denticles, their length longer than basal width. Meso- and metatibiae flattened; outer margin evenly rounded with seven moderate socketed denticles, their length equal to basal width.

Etymology.

L. bullatus = inflated. Named in reference to the tumescent declivity. An adjective.

Distribution.

China (Fujian).

Host plants.

Unknown.

Figures

Figure 78. Dorsal, lateral and declivital view of Truncaudum agnatum, 2.1 - 2.9 mm (A, B, E), and T. bullatum holotype, 1.9 mm (C, D, F).