Wallacellus Hulcr and Cognato

Hulcr, Jiri, 2010, New genera of Palaeotropical Xyleborini (Coleoptera: Curculionidae: Scolytinae) based on congruence between morphological and molecular characters, Zootaxa 2717, pp. 1-33 : 27-29

Genus Wallacellus Hulcr and Cognato , gen. n.

Type species. Wallacellus piceus ( Motschulsky, 1863) .

Diagnosis. Characters distinguishing Wallacellus from Euwallacea include: lateral aspect of pronotum basic type or flattened, elongated anteriad, not tall; body slender (length/width ratio 2.8 to 3.2), never longer than 3.5 mm, pronotal posterocoxal process slightly to distinctly inflated, protibial margin rounded, with 8 or more small denticles; apex of interstria 1 broadened, often elevated; declivital interstria 1 with tubercles distinctly larger than other interstria. Characters distinguishing Wallacellus from Xyleborus include: anterior costa of segment one on antennal club straight or slightly concave, not distinctly concave; anterolateral margins of pronotum slightly inflated, pronotum subquadrate (not rounded); protibiae with 8 or more small socketed denticles, sockets not enlarged; prosternal posterocoxal process slightly inflated (not distinctly inflated); declivity broadened laterally, elytral apex appears angulate; interstria 1 broadened on declivity, often elevated, tubercles on declivital interstria 1 larger than on other interstriae.

Description. Eyes emarginate, upper portion of eyes smaller than lower part. Antennal club circular, club type two (obliquely truncated, second segment visible on posterior side), or three (anterior costa of first segment straight or convex). First segment of club covering most of posterior face, its margin costate, may appear pubescent on posterior side. Second segment visible on both sides of the club, soft and thin on anterior side. Third segment pubescent on the anterior side of club, narrow on the posterior side. First segment of antennal funicle shorter than pedicel, only in W. striatulus longer than pedicel. Funicle composed of 4 segments, scapus regularly thick. Narrow triangular submentum slightly to deeply impressed. Serrations on anterior edge of pronotum absent. Pronotum from lateral view basic (type 0), or elongated, with low summit (type 7), from dorsal view subquadrate (type 3), or elongated and subquadrate (type 8), with anterolateral corners slightly inflated. Pronotal disc shining or smoothly alutaceous, with small punctures, lateral edge of pronotum obliquely costate. Procoxae contiguous, prosternal posterocoxal process conical and slightly to distinctly inflated. No mycangial tufts on basis of pronotum or elytra. Scutellum flat, flush with elytra. Elytral bases straight, with oblique edge, elytral disc longer than declivity, slightly to distinctly convex, punctures on elytral disc in strial lines. Lateral profile of elytral declivity slowly descending, often flat. Declivity broadened postero-laterally, posterolateral margins almost straight, elytral apex appears angulate. Posterolateral declivital costa ending in 7th interstriae. Declivity never with conspicuous pubescence. Declivital tubercles forming synapomorphic pattern: tubercles most conspicuous on interstriae 1, minute or absent on interstriae 2, intermediate on interstriae 3 and beyond. Striae may be slightly impressed, particularly striae 2, in W. striatulus striae and interstriae form ridges and furrows. First interstriae are slightly to distinctly broadened on declivity, bearing granules or tubercles. Protibial edge rounded, protibial denticles small, bases of the denticles not enlarged, with 6 to 8 denticles. Length: 2.0-2.9 mm. Color reddish brown to dark brown or black.

Etymology. M (masculine English origin, ICZN Code 30.2.), recognizes Alfred R. Wallace’s contribution to the development of Indopacific biogeography.

Comments. Establishment of Wallacellus gen. n. is the first attempt to revise the variable Euwallacea - Wallacellus - Xyleborus complex, where most characters are symplesiomorphic. Only one species of Wallacellus was represented in the molecular phylogeny of Cognato et al. (2010), thus the genus is designated using only morphological characters.