Webbia aculeata Sittichaya, Smith & Beaver, 2023

Sittichaya, Wisut, Smith, Sarah M. & Beaver, Roger A., 2023, New species, taxonomic changes and newly recorded species of Webbia Hopkins, ambrosia beetles from Thailand and neighbouring countries (Coleoptera: Curculionidae: Scolytinae: Xyleborini), Zootaxa 5264 (1), pp. 47-63 : 49-51

Webbia aculeata Sittichaya, Smith & Beaver sp. nov.

Fig. 1

Type material. Holotype, female, THAILAND, Ranong Province, Khlong Na Kha Wildlife Sanctuary , 9°27'36.1"N 98°31'19.2"E, tropical rainforest, 140msl, ethanol baited trap, 01.vii.2014, W. Sittichaya ( NHMW).

Diagnosis. 2.2 mm long, three times as long as wide. This species is distinguished by the circumdeclivital margin denticulate; elytral declivity rather smooth and strongly shining; declivital face flat, not impressed; declivital striae very shallowly punctate, punctures inconspicuous; declivital interstriae granulate, granules small each with short brownish hair-like setae; elytra with strong, robust processes with acute apices arising from the posterolateral declivital margin; each elytral apex with a small triangular, horizontal process close to suture.

The species is most similar to Webbia cornuta Schedl , W. granulosa sp. nov. and W. hatanakai Browne , but can be distinguished by the greater size of the spines on the posterolateral margin of elytra, with their length greater than their width at the base. The spines are smaller and shorter in the other three species.

Description (female) 2.18 mm long (n=1); 3.0× as long as wide. Bicolored, head, pronotum, declivital summit, declivital face and processes brown; elytral disc and appendages pale yellowish brown, nearly white. Elytra semitransparent. Head. Epistoma entire, transverse, with a row of hair-like setae, setae short. Frons flat to upper level of eyes; subshining, with feebly elevated median line; shagreened, finely granulate, granules becoming smaller from vertex toward epistoma, sparsely covered with long erect hair-like setae. Eyes moderately emarginate just above antennal insertion,upper part slightly smaller than lower part.Submentum triangular,deeply impressed.Antennal scape clavate, thick, slightly longer than club. Pedicel narrower than scape, 2× longer than funicle. Funicle 2-segmented. Club flattened, circular, as broad as tall, type 2, segment 1 corneous, corneous portion small, occupying approximately basal 1/4 of club, its anterior margin straight on anterior face; segments 1 and 2 visible on posterior face, segment 2 narrow, pubescent on both anterior and posterior sides. Pronotum: 1.33× as long as wide. From dorsal view long and quadrate frontally, type a, sides parallel in basal 3/4, quadrate anteriorly; anterior margin feebly emarginate medially, margin without serrations. In lateral view long, flattened and bulging frontally, type b, disc flat, summit approximately in anterior quarter. Anterior slope subshining, with transverse, fine, narrow asperities, becoming lower and more strongly transverse towards summit bearing short, fine, semi-recumbent hair‒like setae, setae longest at anterior margin becoming shorter posteriorly and ending at middle of anterior slope; disc subshining, alutaceous, glabrous, densely with minute punctures. Lateral margins weak carinate. Base feebly bisinuate, posterior angles rounded. Scutellum: minute, scarcely visible. Elytra: 1.65× as long as wide, 1.28× as long as pronotum. Elytral bases sinuate, with fringe of mycangial setae along the costate margin, humeral angles rounded, sides subparallel in basal 4/5, then angulate to apex. Apical margin with small, triangular, horizontally-directed processes. Disc convex, glabrous, shining, subtransparent; striae shallowly punctate, punctures minute, subcontiguous, separated by about half their diameter; interstriae flat, glabrous, 2× as wide as striae. Declivity abruptly truncate, declivital margins armed with short, truncate denticles, each denticle with several short, brownish hair-like setae; declivital face flat, not impressed, rather smooth and strongly shining, bearing widely spaced setae; striae very shallowly punctate, punctures inconspicuous, each with a very short and fine seta; interstriae granulate, granules small, widely spaced, cuticle between granules flat and smooth, each granule with short brownish hair-like seta each 2× as long as strial setae. Posterolateral margin of declivity armed with a robust process, its length greater than its width at the base, basal part quadrate, apically with an upwardly and inwardly directed, sharp spine. Apical margin with small, triangular, horizontally-directed processes. Legs. Procoxae contiguous. Protibiae slender, broadest at middle; posterior face inflated, granulate; outer margin with 12 small socketed denticles, their length shorter than basal width. Meso- and metatibiae with outer margin rounded, broadest at middle, each with 12 small socketed denticles, posterior faces flat, unarmed; anterior faces very finely granulate.

Etymology. L. aculeatus = sharply-pointed. Adjective. The name refers to the elytral posterolateral processes with pointed spines.

Distribution. Thailand (Ranong).

Host plants. Unknown.

Figures

FIGURE 1. Webbia aculeata sp. nov. holotype A) dorsal view; B) lateral view; C) postero-lateral view; D) frons; E) venter and antennae; F) declivital face.