Thursday, 30 September 2010

Featured insect: Oxymorostes riedeli (Coleoptera: Hybosoridae)

Oxymorostes riedeli Copyright Mario Toledo
It's been an interesting month, and what better way to finish it off than with an interesting beetle! I present Oxymorostes riedeli, a bizarre leaf-litter inhabiting beetle from West Papua described in 2009 by Alberto Ballerio. Not only does this beetle look wierd with its out-of-proportion pronotum being wider than its elytra, but it also has several cavities in its mouthparts and underside the function of which is currently unknown. Several other beetles, most notably the bark beetles, have similar cavities known as mycangia in which they store the spores of their food fungus. This is unlikely to be the case in this beetle though, as fungal spores have not been found in them. They did however have an "unknown substance of uncertain origin" inside them, for which there was "an unsuccessful attempt was made to analyze the substance". Just adds to the wierdness really.

Oxymorostes is placed in the subfamily Ceratocanthinae of the Hybosoridae, a worldwide though little known family similar to the scarab beetles. The Ceratocanthinae in general are pretty cool, with some very beautiful species in it such as this currently unknown Eusphaeropeltis species from Malaysia.

Eusphaeropeltis species


Ballerio A. 2009. Unusual morphology in a new genus and species of Ceratocanthinae from New Guinea (Coleoptera: Scarabaeoidea: Hybosoridae). The Coleopterists Bulletin 63(1):44-53

Ballerio A, Maruyama M. 2010. The Ceratocanthinae of Ulu Gombak: high species richness at a single site, with descriptions of three new species and an annotated checklist of the Ceratochanthinae of Western Malaysia and Sinagapore (Coleoptera, Scarabaeoidea, Hybsoridae). Zookeys 34:77-104

Grebennikov VV, Leschen RAB. 2010. External exoskeletal cavities in Coleoptera and their possible mycangial functions. Entomological Science 134:81-98

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