Diuncus haberkorni ( Eggers 1920 ) Eggers, 1920

Hulcr, Jiri & Cognato, Anthony I., 2009, Three new genera of oriental Xyleborina (Coleoptera: Curculionidae: Scolytinae), Zootaxa 2204, pp. 19-36 : 31-32

Diuncus haberkorni ( Eggers 1920) comb. n.

Previous genus: Xyleborus

Diagnosis: Extremely variable in size. All observed individuals orange to light brown, elytra darker than pronotum. Distinguishable from other Diuncus by two pairs of equal, medium-size teeth in interstriae 2 and 3, the pair in the third interstria is positioned lower towards the middle of declivity, the teeth are tubercle-like, with broad base, not spine-like or hook-like. Interstriae 4, 5, 6 on upper part of declivity sometimes with rows of small serrations (minute in the lectotype specimen). The declivital surface varies widely, with striae impressed or not, from bald and shining to covered with dense appressed pubescence or opaque, from smooth to covered with minute interstrial spines. Diuncus haberkorni is very similar to Diuncus conidens , and differs by the absence of granules or tubercles on the elevated end of interstria 1 and by much smaller tibial denticles. It is also very similar to Diuncus quadrispinosulus , in which the declivital teeth in striae 2 and 3 are minute, sharply pointed, recurved, and both pairs positioned at the very summit of declivity. However, species splits based on these very plastic characters may be artificial, and may not define monophyletic lineages.

Length: 1.5–2.5 mm.

Discussion. Often identified as Xyleborus approximatus , which is probably its junior synonym.

Biology: Beaver and Browne (1978) noted that galleries of this species in Penang, Malaysia, were started in close proximity to those of Xylosandrus mancus . Though the species is commonly found creating galleries next to other ambrosia species in the typical parasitic fashion, it is also sometimes found apparently unassociated with any other species. The strictness of its fungus-stealing habit is unclear. The variation may stem from the fact that the 'species' as determined here by the plastic characters is unlikely to be monophyletic.

Examined material: Africa, D. O. Afrika, Amani, (lectotype, USNM); Malaysia, ( USNM); Malaysia, Sabah, Danum Valley, J. Hulcr 2006; New Guinea, Morobe Province, Bulolo ( FICB, 62 indiv.); Thailand, Khao Sok NP (S. Dole); unknown locality (3, BMNH); PNG: Oro Prov. (2), J. Hulcr 2006.