Debus pumilus (Eggers), comb. n.

Xyleborus pumilus Eggers (1923)

Xyleborus ipidia Schedl (1972a), syn. n.

Xyleborus cylindricus Eggers (1927a), syn. n. (complete taxonomic history in Wood and Bright, 1992)

Specimens examined. D. pumilus: Indonesia, Sumatra (lectotype, USNM); Malaysia, Sabah, Danum Valley (66, Hulcr det., MSUC.); New Guinea, Morobe Province, Bulolo (1, FICB); New Guinea, Gulf Province, Ivimka (1, R. A. Beaver det., UCD); New Guinea, Madang Prov. (960, Hulcr det., MSUC), Oro Prov. (20, Hulcr det., MSUC); West Sepik (370, Hulcr det., MSUC). X. ipidia: New Guinea, New Ireland (paratype, FICB), New Guinea, New Ireland (NHMW). X. cylindricus: Philippines, Luzon, Balbalan (lectotype, USNM).

Comments. Placement of D. pumilus in Debus was confirmed by molecular phylogenetic analysis (72% and 74% posterior probability, Cognato et al., 2011). It is one of the smallest and most slender Debus specie s. The declivity is only slightly excavated or entirely flat (which is unusual in Debus), the apex of elytra is usually flat, or slightly emarginate. Also declivital denticles are smaller than in other Debus (except some D. emarginatus).

The holotype of X. ipidia is probably lost. Paratypes of X. ipidia and holotype of D. pumilus are essentially identical, except for the declivital spines, which are slightly less produced in D. pumilus . The holotype of X. cylindricus is nearly identical to the holotype of D. pumilus, except that the largest pair of denticles on declivity is slightly displaced towards the edge, making declivity appear slightly excavated. Other variants of the D. pumilus - group exist throughout Pacific islands, differing in details of declivital armature and puncturation (R. A. Beaver, pers, comm.). They are most likely insular deviations of the variable D. pumilus declivity.