Xylopertha Guérin-Méneville, 1845

Liu, Lan-Yu & Beaver, Roger A., 2017, A review of the powderpost beetle genus, Xylopertha Guérin-Méneville, 1845, with a new species and new synonymy (Coleoptera: Bostrichidae: Bostrichinae: Xyloperthini), European Journal of Taxonomy 380, pp. 1-22 : 3-7

Genus Xylopertha Guérin-Méneville, 1845

Figs 1–4

Xylopertha Guérin-Méneville, 1845 : XVII.

Xylonites Lesne, 1901: 575 . Synonymy: Fisher 1950: 143.

Paraxylogenes Damoiseau, 1968: 1 , syn. nov.

Type species

Type species of Xylopertha : Apate sinuata Fabricius, 1792 ( Fabricius 1792: 362) . Subsequent designation by Gorham (1883: 215).

Type species of Xylonites : Bostrichus retusus Olivier, 1790 ( Olivier 1790: 110) . Subsequent designation by Fisher (1950: 143). Synonymy of Apate sinuata with Xylopertha retusa: Schilsky (1899: 291) .

Type species of Paraxylogenes : Paraxylogenes pistaciae Damoiseau, 1968 ( Damoiseau 1968: 4) . Original designation.

Diagnosis

Xylopertha is the type genus of Xyloperthini Lesne (1921). The tribe is characterised by the lamelliform intercoxal process of the first abdominal ventrite, and the mandibles crossed at the tips ( Lesne 1921; Fisher 1950; Liu & Schönitzer 2011). The genus is distinguished from all other genera of Xyloperthini by the following combination of characters: frons with upwardly directed hairs ( Fig. 2 ); antenna with nine antennomeres, the funicle with four and the club with three antennomeres, antennomeres of club lacking stiff, erect hairs, with indistinct sensory impressions near the apex of antennomeres 7 and 8, but absent on the last antennomere; pronotum without a lateral carina; elytral suture raised on declivity, but not strongly swollen; last ventrite of male with pleural pieces at sides; last ventrite of female emarginate.

Compared with the other five genera of Xyloperthini with nine antennomeres which occur in the same geographical area as Xylopertha , Scobicia Lesne, 1901 can be distinguished by the strong swelling of the suture on the elytral declivity in both sexes, and the last ventrite of the female is entire not emarginate; Psicula Lesne, 1941 is distinguished by the presence of an uncus on the anterior angles of the pronotum in both sexes, and the absence of pleural pieces in the male; Enneadesmus Mulsant, 1851 and Xylogenes Lesne, 1901 have distinctly delimited sensory areas on the first two segments of the antennal club, and the females of Enneadesmus have the last ventrite entire. The synonymy of Paraxylogenes with Xylopertha is discussed later in the paper.

Description

BODY. Elongate, cylindrical, 4–8 mm long.

HEAD. Deeply inserted in prothorax, not visible from above. Frons simple, finely punctured, with fine, upwardly directed hairs, denser and much longer in female, fronto-clypeal suture distinct at sides,

strongly impressed in middle; clypeus transverse, finely and densely punctured; labrum transverse with a fringe of long hairs along anterior margin. Mandibles subequal, sharply pointed. Eyes small, oval, strongly projecting. Antenna with 9 antennomeres, first antennomere elongate, about twice as long as oval second, antennomeres 3–6 forming a loose funicle, each antennomere transverse, the fifth widest, together about as long as first antennomere of club, antennomeres 7–9 forming the elongate, compressed club, each antennomere of club with a dense covering of short, recumbent hairs, lacking distinct, clearly defined sensory impressions on all segments, antennomeres 7 and 8 subquadrate, subequal in length, last antennomere more elongate, oval.

PRONOTUM. Slightly wider than long, anterior angles with a small upcurved tooth without an uncus inserted a little behind margin, anterior margin between teeth slightly concave, not depressed behind the margin; area above anterior margin flat or weakly impressed, strongly, densely punctured, without teeth;

sides moderately to broadly rounded, converging more strongly anteriorly, posterior angles broadly rounded, without a lateral carina, postero-lateral area with fine rugulosities; disc smooth, shining, indistinctly punctured, glabrous; anterior slope with 3 or 4 large, upcurved teeth antero-laterally on each side behind the marginal tooth, with smaller teeth between them.

SCUTELLUM. Small, tongue-shaped, shining, finely punctured.

ELYTRA. Subequal to pronotum in width, strongly convex, shining, strongly, rather evenly punctured on disc, glabrous anteriorly, the declivity usually strongly sexually dimorphic ( Fig. 1A–F ).

LEGS. Subequal in length, procoxae contiguous, mesocoxae narrowly separated, protibiae grooved on external face, widened to apex, posterior tibiae with long hairs on outer side. Second and third segments of tarsi usually distinctly wider than the following segments.

ABDOMEN. Intercoxal process of first abdominal ventrite lamelliform, the ventral face a little widened in one species ( X. praeusta (Germar, 1817)) .

Sexual dimorphism

The genus shows strong sexual dimorphism in both the vestiture of the frons, and in the form and sculpture of the elytral declivity (except in X. reflexicauda ), as well as in the genitalia. In the female the frons is more densely and finely punctured, and the upwardly directed hairs are much longer and denser than in the male. In the male, the elytral declivity is more angularly separated from the disc, and the elytral apices are either conjointly rounded or separated by a small V-shaped emargination. In the female, the disc curves more evenly into the declivity, and the elytral apices are strongly emarginate, the emargination partly filled by a pair of ventrally-directed processes ( Fig. 3A–C ) (except in X. reflexicauda ; Fig. 3D ). The last abdominal ventrite of the male has pleural pieces which converge posteriorly towards the midline; these are absent, and the last ventrite is emarginate in the female.

Distribution

Southern and central Europe, North Africa and Middle East.

Biology

The adults of Xylopertha are polyphagous, usually attacking a taxonomically wide variety of host trees, although they may appear to show some host preferences. They bore into twigs and branches, where they construct a short gallery, usually consisting of a circumferential and one or more longitudinal branches in which the eggs are laid ( Liu et al. 2008). The larvae bore through the wood making extensive galleries filled with fine wood particles and excreta. The new generation of adults emerges through the bark, but may reattack the same stem, so that the whole of the sapwood is eventually converted into fine powder ( Liu et al. 2008). The development time is variable depending on local conditions, and may vary from a few weeks to over a year ( Beeson & Bhatia 1937).

Figures

Fig. 1. Dorsal view of species of Xylopertha Guérin-Méneville, 1845. A. Xylopertha elegans sp. nov., ♂. B. X. elegans sp. nov., ♀. C. X. retusa (Olivier, 1790), ♂. D. X. retusa (Olivier, 1790), ♀. E.X.praeusta(Germar,1817),♂.F.X.praeusta(Germar,1817),♀.G.X.reflexicauda(Lesne,1937),♂. H. X. reflexicauda (Lesne, 1937), ♀. Scalebar = 1 mm.

Fig. 2. Frontal view of the females of species of Xylopertha Guérin-Méneville, 1845. A. Xylopertha retusa (Olivier, 1790). B. X. praeusta (Germar, 1817). C. X. elegans sp. nov. D. X. reflexicauda (Lesne, 1937). Scale bar = 1 mm.

Fig. 3. Declivity of the females of species of Xylopertha Guérin-Méneville, 1845. A. Xylopertha retusa (Olivier, 1790). B. X. praeusta(Germar, 1817). C. X.elegans sp. nov. D. X.reflexicauda (Lesne, 1937). Scale bar = 1 mm.

Fig. 4. Last 3 or 4 visible abdominal ventrites of females of species of Xylopertha Guérin-Méneville, 1845. A. Xylopertha retusa (Olivier, 1790). B. X. elegans sp. nov. C. X. praeusta (Germar, 1817). D. X.reflexicauda (Lesne, 1937). Scale bar = 1 mm.