`These are Elaphe according to most taxonomists. Yes Utiger et al. include more ratsnakes (all of which are members of the genus Elaphe according to most taxonomists)'



I hate to nitpick, but Coronella, Lampropeltis, Arizona, Pituophis, Bogertophis, and Senticolis are all called `ratsnakes' in informal terminology (Lopez and Maxson call all members of Lampropeltini `ratsnakes' for instance) but these obviously are not Elaphe.



`in their study than most authors, but it does not change anything. All of the members of Elaphe share a more recent common ancestor with each other than any of them does with any racer, including Ptyas, in Lopez and Maxson (1995).'



No. Only four species of Elaphe (five if you wanted to include Rhinechis scalaris--a taxon created explicitly on the basis of morphological disparity, for what it's worth) share a more recent common ancestor than the other taxa in Lopez and Maxson's study. Without data about all of the members of Elaphe sensu lato, no conclusions can be reached about all of the members of Elaphe sensu lato.



`The same is true in Utiger et al. All members of Elaphe (including E. mandarina and E. conspicillata) share a more recent common ancestor with each other than any of them does with Ptyas. There simply is no evidence that any of the large number of ratsnake species in Utiger et al.'s study is more closely related to the racers than to each other. In other words, there simply is no evidence to support the oft-repeated claim that Elaphe is polyphyletic.'



This, again, has already been addressed. Mono- or paraphyly cannot be supported in the absence of any well-supported relationships among the taxa of Elaphe sensu lato.



`I don't know what your conclusion is'



My conclusion (which I had thought was obvious) is that the difference in outgroup support for Ptyas between Lopez and Maxson and Utiger et al.'s studies supports polyphyly of Elaphe sensu lato. Your conclusion, apparently, is that they suggest flaws with Utiger et al.'s data.



`but I do know that there is no evidence Elaphe is polyphyletic.'



In the face of multiple independent studies concluding that Elaphe sensu lato is polyphyletic? Even if you don't think it's -good- evidence, there clearly is evidence.



`You have denied that they splinter Elaphe because of an ideological intolerance of paraphyly. But you cannot provide evidence Elaphe is polyphyletic and you cannot provide evidence that Elaphe is a morphologically disparate group.'



I have already provided citations of several studies supporting both polyphyly and morphological disparity.



`If there is a fourth reason why they splinter Elaphe, I don't know what it may be. Therefore I will maintain that they splinter Elaphe because of their scientifically untenable intolerance of paraphyletic taxa.'



And, predictably enough, I'll continue to disagree.



Patrick Alexander

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