Posted by:
aspidoscelis
at Wed Aug 31 18:35:50 2005 [ Report Abuse ] [ Email Message ] [ Show All Posts by aspidoscelis ]
"Is there a general consensus on placing the North American skinks (Eumeces) in the resurrected genus Plestiodon?
The evidence for paraphyly seems pretty strong."
So, I can't readily get a hold of the Griffith et al. morphological paper, but I'm looking at the Schmitz et al. mitochondrial DNA paper (in Hamadryad, v. 28, from 2004), and it seems that they have reasonably good evidence that Neoseps, Scincus, and Scincopus are nested within Eumeces, but they have poor support for a lot of nodes in their tree and, because of very limited outgroup sampling, they have no data to test for polyphyly of the genus as a whole. This would mean that strict cladists, rejecting all paraphyletic taxa, would have to say that either: 1. Eumeces has to be split, though the current data aren't good enough to tell them *where* to split, or 2. the three smaller genera must be lumped into Eumeces.
However, the generic recommendations made by Schmitz et al. are not based on a rejection of paraphyly. Instead, they suggest recognition of each of their three main clades as genera, and lumping the smaller genera (Scincus, Scincopus, and Neoseps) into these genera. But Eumeces with the smaller genera lumped into it is a monophyletic taxon in their tree, so there's no need to split it.
The gist is... from here, the Schmitz et al. paper just looks like another case of poorly done herpetological taxonomy. They present data that can't unambiguously resolve the situation and then suggest taxonomic changes without giving a clear argument for them. Maybe Griffith et al. do present a good argument for splitting Eumeces, I don't know.
Patrick Alexander
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