Fortiborus 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 : 17-18

Genus Fortiborus Hulcr and Cognato , gen. n.

Type species. Xyleborus major Stebbing, 1909 .

Diagnosis. The genus most closely related to Fortiborus is Euwallacea ( Fig. 9 ). Characters distinguishing Fortiborus from Euwallacea include: margin of the first segment of antennal club concave, recurved (may appear straight); antennal club wider than long in several Fortiborus ; anterior edge of pronotum produced anteriad, bearing a row of serrations (except. F. anisopterae ); protibiae rounded (except in F. indigens ), bearing seven or more denticles, protibial spur absent.

Description. This genus includes some of the largest xyleborine species (5.2- 7 mm). Color uniformly dark brown or black. Upper portion of eyes conspicuously large. Antennal club type three (with first segment straight or convex), or four (first segment small, second and third prominent on both sides). First segment of antennal funicle longer than pedicel, its base stalk-like, funicle composed of 4 segments. Frons above epistoma rugged, coarsely punctate. Submentum shallowly to deeply impressed, shaped as very narrow triangle. Anterior edge of pronotum with distinct row of serrations, in most species conspicuously produced. Pronotum from lateral view tall (type 2), or rounded and robust (type 5), from dorsal view subquadrate (type 3), or quadrate, robust (type 4). Pronotal disc shining or smoothly alutaceous, with small punctures, or densely and evenly punctured, lateral edge of pronotum obliquely costate, usually with pointed shoulder. Procoxae contiguous, prosternal posterocoxal process conical and slightly inflated. No mycangial tufts on pronotum or bases of elytra. Scutellum flat, flush with elytra. Elytral bases straight, with oblique edge. Elytral disc longer than declivity, slightly to distinctly convex, or distinctly concave. Punctures on elytral disc in strial lines. Boundary between elytral disc and declivity indistinct, end of disc rounded and smoothly transitioning into declivity. Lateral profile of elytral declivity convex, especially towards the apex, rarely steep, excavated in one species. Dorsal profile of elytral apex rounded, usually broadened laterally. Elytral declivity with few setae or scales, not conspicuously pubescent. Posterolateral declivital costa ending in 7th interstriae, in one species surrounding most of declivity. Declivital armature variable: devoid of tubercles, or uniform granules present, or no tubercles on interstria 1 (sutural) and several tubercles on interstriae 2, 3 and beyond, or tubercles on elevated costa around declivity. First interstriae parallel. 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, with setae only. Protibial denticles small, bases of the denticles slightly enlarged, conical, 6 to 8 protibial denticles present.

Comments. Fortiborus was not included in the molecular phylogenetic analysis of Cognato et al. (2010). Taxonomic changes presented here are based only on morphological characters. When the cladogram ( Fig. 9 ) is rooted with Xyleborus , Euwallacea appears to be paraphyletic with respect to Fortiborus . It is possible that Fortiborus is evolutionarily derived from Euwallacea .

Etymology. L, masculine, name refers to the robust body.

Figures

FIGURE 9. Morphology-based cladistic analysis of species previously placed in Euwallacea, Xyleborus, and several similar species of unclear affiliation. Combinable-component consensus of 72 MP trees, (113 steps). Numbers at nodes indicate Bremer support.