Holy crud-covered carabids Batman
November 18th, 2016
Jim Liebherr recently completed the taxonomic revision of the Cyphocoleus carabid beetles; 22 species restricted to the island microcontinent of New Caledonia. Twelve of the species are newly described in the open access journal, Deutsche Entomologische Zeitschrift (DEZ for short): http://dez.pensoft.net/articles.php?id=10241.
The beetles are remarkable for their very divergent morphology, which at first glance would suggest they are not evolutionarily related. But not so Robin, they form a monophyletic group (meaning they are all descended from a single ancestor). The group is remarkable for the unusual structure of their mouthparts. The galea, or outer lobe of the maxilla is single segmented, versus made up of two segments as in nearly all carabid beetles. In fact, this character plus many other internal anatomical characters put Cyphocoleus in a new subtribe of the carabid tribe Odacanthini; the subtribe Homethina.
The Homethina are an old group, as exhibited by the taxon membership. Accompanying Cyphocoleus in this subtribe are the genera Homethes and Aeolodermus of Australia, Stenocheila and Diplacanthogaster in South America, and Quammenis in Costa Rica. These biogeographic relationships support the presence of Cyphocoleus on New Caledonia since the Cretaceous Period, with the entire group related across Antarctica until the Miocene when that continent was a green, verdant shrubby grassland.
The really cool thing about these beetles Robin, is the environmental patina that covers the body in some of the species. This was first seen by Jong Kyun Park and Kip Will, who described two of the species with this character. Beetles in full regalia look like little bits of bark and leaf litter.
But clean off that crud, and they look just like other beetles, kind of....
except for the elongate and bizarre cricket-bat shaped setae covering their bodies that presumably help hold on the crud.
Well Robin, I see you are getting a little glassy-eyed, kind of beetle-browed in a creepy kind of way, so it's time for some action. But if you want to learn more, go to the DEZ and check out this paper plus many more. They are all open access.