Weevil Ball (Taxon of the Week: Diorymerina)

Diorymerus lancifer, from Davis (2009).

The Diorymerina are a South American subtribe of the weevil subfamily Baridinae. Alonso-Zarazaga & Lyal (1999) include ten genera in the Diorymerina according to the International Weevil Community Website* (though this listing differs slightly from that given by Casey, 1922) but available info on members of the group appears to be rather sparse to almost non-existent. Which is a pity because they are certainly eye-catching animals.

*I do think it rather neat that there's an "International Weevil Community".

Baridinae as a whole are characterised by a rounded body shape but in the Diorymerina this is taken to an extreme. The dorsal profile of diorymerins is highly arched, almost circular, and at least some diorymerins have bodies nearly as deep as they are long (Casey, 1922; Davis, 2009). All members of the Diorymerina are glossy in appearance and usually such colours as black or mahogany brown though Bonomius aeneoviridis is a bright metallic green. The beak of diorymerins is usually relatively short and stout compared to other weevils.


Hiotus inflatus, from Davis (2009) again.

Lima (1956) recorded species of Diorymerina feeding on shoots and seeds of Malpighiaceae trees but other than that most species seem not to have been touched on since their original morphological descriptions, and even those are scattered and difficult to locate. Significant landmarks appear to be Casey (1922) and Hustache (1950), the latter being the first part of the rather unpleasant 'Nouveaux Barinae Sud Américains'. Most of this publication's eccentricities may perhaps be excused by its unusual publication history (Kuschel, 1983): while the original manuscript was prepared in 1929, it languished for twenty years due to lack of funding and was not published until after the author's death. Nevertheless, the four parts together add up to over three hundred pages of bare species descriptions with absolutely no illustrations, usually no explicit comparisons with previously described taxa and a whole universe of typological errors.

REFERENCES

Alonso-Zarazaga, M. A., & C. H. C. Lyal. 1999. A world catalogue of families and genera of Curculionoidea (Insecta: Coleoptera) (excepting Scolytidae and Platypodidae). Barcelona.

Casey, T. L. 1922. Studies in the rhyncophorous subfamily Barinae of the Brazilian fauna. Memoirs on the Coleoptera 10: 1-520.

Davis, S. R. 2009. Morphology of Baridinae and related groups (Coleoptera, Curculionidae). ZooKeys 10: 1-136.

Kuschel, G. 1983. New synonymies and combinations of Baridinae from the Neotropic and Nearctic regions (Coleoptera: Curculionidae). Coleopterists Bulletin 37 (1): 34-44.

Lima, A. M. da C. 1956. Insetos do Brasil vol. 10. Coleópteros. Esc. Nac. Agronomia: Rio de Janeiro.