Posted by:
RSNewton
at Sat Aug 2 00:43:22 2003 [ Email Message ] [ Show All Posts by RSNewton ]
Hello. I would disagree that my critiques are "little more than a summary of that paper's findings."
The extremely short branch lengths within the "Southern clade" and the fact that some of these localities were probably too cold to support any population of snake as little as 13,000 years ago suggest to me that these particular populations may only represent a post-glacial expansion of the range of a small remnant population of a snake that has found much
better success to the north. Perhaps C. bottae has fared better to the north because of lack of competition from a closely related species: Lichanura trivirgata. This is indeed an interpretation of the mtDNA data that Rodriguez-Robles et al. do not make. What they appear to be looking for are clades. And that is exactly what they see. If this "clade" is really a post-glacial range expansion of a remnant population, then it is not deserving of
any taxonomic recognition. To recognize this "clade" as a full species even though there is no evidence of reproductive isolation or any morphological character that would distinguish it from other populations of C. bottae is simply scientifically untenable.
It is certainly true that I have not added to their evidence. Nevertheless, their own data do not support their conclusion that umbratica is a valid species. This is a point that Rodriguez-Robles et al. would certainly not make. That is why my posts are more than a summary of their findings. It is a different interpretation, one that I believe is more consistent with the available data.
Regards.
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RE: I got a slightly different impression from the posts.... - RSNewton, Sat Aug 2 00:43:22 2003