Beaverium Hulcr & Cognato
Creators: name: Hulcr, Jiri
name: Cognato, Anthony I.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Curculionidae
Beaverium

description: Genus Beaverium Hulcr & Cognato gen. n.
Type species: Beaverium insulindicus (Eggers, 1923).
Diagnosis: Beaverium spp. can be distinguished from most other Xyleborina by the large size, very robust, rounded elytral disc and distinctly flattened elytral declivity broadened posterolaterally. The genus is unique among Xyleborina in that the posterolateral declivital costa ends on the 5th interstriae.
Description: Eyes deeply emarginate, sometimes almost disjunct, upper portion of eyes as large as the lower part, or even larger. Antennal club more or less circular shape, club type three (with first segment straight or convex), or four (first segment small, second and third prominent on both sides). First segment of club approximately straight on anterior face, or convex and small, margin of the first segment mostly costate, may appear soft and pubescent on club margins. Second segment of club variable: visible on both sides of the club, but soft, or the corneous part on the anterior side only, or corneous on both sides of club, but sinuate, not circular. Third segment of club clearly visible on both sides of the club. First segment of antennal funicle either shorter than pedicel, or sometimes longer with its base stalk-like. Funicle composed of 4 segments, scapus of regular shape and thickness. Frons above epistoma rugged, coarsely punctate. Submentum slightly impressed, narrow (shaped as a very shallow triangle), or a narrow triangle. Anterior edge of pronotum usually with short continuous elevated recurved carina, in one species the edge is blunt. Pronotum from lateral view tall (type 2), or rounded and robust (type 5). From dorsal view it is conical (type 0), or rounded (type 1), or subquadrate (type 3). Pronotal disc densely and evenly punctured, often with asperities resembling those on the frontal slope, lateral edge of pronotum obliquely costate, often with a distinctly elevated shoulder. Procoxae contiguous, prosternal posterocoxal process short, conical or flat, inconspicuous, or conical and slightly inflated. No signs of mesosternal or elytral mycangia or the associated setae. Scutellum flat, flush with elytra. Elytral bases straight, with oblique edge, elytral disc longer than or equally long as declivity and usually convex or bulging, rarely impressed, "saddle-like". Punctures on elytral disc in strial lines, but the lines disappear and punctures become confused on the declivity. Lateral profile of elytral declivity slowly descending or steep, flat or excavated, dorsal profile of elytral end broadened laterally, or shallowly emarginate. Elytral declivity with few setae or scales, not conspicuously pubescent. Posterolateral costa ends in 5th interstriae. The inner part of declivity has no tubercles, or only uniform small granules. Striae and interstriae on the upper part of declivity are even, not elevated or impressed. First interstriae are parallel throughout the elytra. Protibiae obliquely triangular, broadest at 2/3 of the length, or distinctly triangular, slender on the upper part, broad and denticulate on the lower part. Posterior side of protibia flat, smooth, with setae only. Protibial denticles can be small but mostly are large and distinctly longer than wide, bases of the denticles slightly elevated, or distinctly enlarged, conical, usually between 6 and 8 protibial denticles present. Metatibiae not enlarged. Large to very large species, robust, 3.8–7.5 mm. Mostly uniformly dark brown or black, pronotum sometimes lighter, interstriae on elytra often reddish.
Discussion. Etymology: The genus is named in honor of Roger A. Beaver, one of the most prominent contemporary bark beetle taxonomists, whose indispensable assistance and material greatly helped the completion of this project. Gender masculine (masculine English origin, ICZN Code 30.2.).
Schedl (1942) includes the following species into the " insulindicus-sweyzeyi " species-group: Xyleborus insulindicus, X. sweyzeyi Beeson, X. sundaensis, X. aplanatideclivis. According to Beeson's (1929) illustration of X. swezeyi, the species likely belongs to the genus Beaverium (specimens not available for examination). Early authors describing various species of this genus often used declivital punctures as important characters, and distinguished "confused punctures" from "punctures in lines". In reality, the strial punctures are always aligned, while interstrial punctures are almost never aligned and rarely present as only one row per interstria. The above mentioned distinction actually describes different sizes of strial and interstrial punctures, where 1) if interstrial punctures are small, then the strial punctures appear prominent and the elytrae appear striatopunctate, while 2) if interstrial punctures are as large as strial ones, the whole surface appears confused. Furthermore, upon examination of many specimens of various forms previously ascribed to various species, this character actually forms a continuum of variation which transcends specific boundaries and often does not co-vary with other characters.
description: Published as part of Hulcr, Jiri & Cognato, Anthony I., 2009, Three new genera of oriental Xyleborina (Coleoptera: Curculionidae: Scolytinae), pp. 19-36 in Zootaxa 2204 on page 25, DOI: 10.5281/zenodo.189700