Monday, June 20, 2016

Plociopterus ain't no myrmecophile!


In a paper just published in Coleopterists Bulletin (pdf here), Mariana Chani-Posse and I moved two myrmecophilous species of “Xanthopygina” in Philonthina. Both species had been described by Wasmann 1925 in the genus Plociopterus. And so for the last 90 or so years, Plociopterus was known to have two myrmecophilous species. Unfortunately, several authors discussing the origin of myrmecophily in Staphylinidae (or at least specifically for Staphylinini) was using this as an example of independent evolution of myrmecophilous life style. The problem was that nobody had checked the specimens since the original description, because none of those species belonged in Plociopterus. They are Belonuchus (at least until the genus is revised) and for those keeping score at home, this is also the wrong subtribe…

The moral of the story is this: people make mistakes and generic concepts change over time, as well as our understanding or higher level relationships. As I have mentioned earlier, If somebody described a taxon 100 years ago, chances are that this taxon now belongs in a different genus or is a synonym of something else. Using raw data in biodiversity studies without going through the lens of a revision is almost guaranteed to lead to erroneous results.

As a side note, Plociopterus is in terrible need of a revision. There are multiple new species awaiting description and many taxa that have to be placed in synonymy. But the genus has an infamous history among Xanthopygina workers: at least twice people have started its revision (both in the lab of my late PhD advisor, Steve Ashe) and both times people abandoned the effort. Perhaps third time’s the charm?