Posted by:
ratsnakehaven
at Sat Sep 17 09:48:06 2005 [ Email Message ] [ Show All Posts by ratsnakehaven ]
>>The problem with ratsnake taxonomy lies in what defines ratsnakes: a bunch of generalised colubrids, formerly lumped together into the genus Elaphe based on a lack of distinctive morphological characters. Morphologically distinctive sistergroups traditionally were outgrouped, which resulted in a highly paraphyletic Elaphe, an outcome considered as invalid by most taxonomist in general and cladists in particular.
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>>For instance, American ratsnakes share a common ancestor with Kingsnakes and Pine/Bull/Gophersnakes. If we outgroup Lampropeltis and Pituophis from Elaphe, which we do, and include the American ratsnakes within Elaphe, which we no longer do, we get a paraphyletic Elaphe. However, if we consider Pantherophis as a sistergroup of Elaphe, which we do, we once again get nice and clean monophyletic taxonomical entities, well at least the American ones.
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>>The resurrection of Pantherophis has been proposed by Utiger et al, based on an analysis of mitochondrial DNA and hemipenal morphometrics. It doesn't mean that Elaphe climacophora isn't similar morpholically to Pantherophis. It does mean, however, that E. climacophora and Pantherophis do not share a common ancester recent enough to belong to the same monophyletical genus.
Herman, that is an excellent response...a great summation of what's going on with ratsnake taxonomy. For the benefit of the strand I'll add a couple of my ideas.
I've been studying the Old World ratsnakes since about 1988 and American ratsnakes before that. I've had most of the Old World snakes at one time or another and believe thay are all related somehow..a common ancestor. Right now I keep Elaphe dione and E. bimaculata, Zamenis situla, Euprepiophis mandarina, and Orthriophis taeniura. I believe they are related and have evolved from a racer-like ratsnake at a time when North American ratsnakes, kingsnakes, etc, were evolving separately.
The N.A. ratsnake ancestor(s) probably arrived in N.A. sometime in the early Miocene, some 20 mya, as there are fossils from the early Miocene. They've been evolving quite a long time and I think deserve a separate genus. The various genera in the Old World are a little more questionable, imo, as there are some obvious relationships.
The endemic ratsnakes of the Japanese islands seem to be related to mainland Asia ratsnakes, but have been evolving a long time too. I think climacophora makes the nicest pet of the three species and is most like the American ratsnakes. It is more closely related to the Old World ratsnakes, however, and could be similar to Pantherophis obsoleta in the sense that it has a similar habitat and behaviors.
Good luck with your snakes. I sure enjoyed mine while working with that species.
Terry
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Ratsnake Haven...researching ratsnakes since 1988 
Ratsnake Haven Group...an information providing list site.
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Very well put... - ratsnakehaven, Sat Sep 17 09:48:06 2005