`The common name of the species classified in Ptyas is also ratsnake.'



Indeed. Another taxon that causes your previous statement to be inaccurate.



` Lopez and Maxson is calling Ptyas a racer. All of the racers in Lopez and Maxson's paper falls outside of the "ratsnake" clade, including Gonyosoma, which is another racer that has the common name of "ratsnake." The important thing to remember is that all species of Elaphe recognized by most taxonomists form a clade with the Lampropeltini. Lopez and Maxson call this clade ratsnakes. I have no problem with it. After all the Lampropeltini includes species that are not in Lampropeltis.'



Fine with me. It just indicates a (fairly minor) error on your part.



`The claim that Utiger et al. delimited Elaphe on the basis of morphological disparity is unsupported.'



Weakly supported, I'd say, but either way, the claim that the taxa they created are `morphologically indistinguishable' is also unsupported.



`I am not sure what you mean, but as I said, all of the species of Elaphe in Lopez and Maxson are more closely related to each other than they are to Ptyas or any other racer.'



Agreed. The problem, as I mentioned, is that they have very few species of Elaphe sensu lato to work with, and can't draw any conclusions about Elaphe sensu lato as a whole.



`Similarly, all of the species that other folks have classified in Elaphe (but which Utiger splinter into many different genera) are also more closely related to each other than any of them is to Ptyas. That is strong evidence that Elaphe is not polyphyletic,'



I disagree, because, as already discussed, there are no well-supported relationships among the genera split from Elaphe sensu lato.



`and Tong et al. (Acta Zoological Sinica) independently verify this fact in their study.'



Which neither of us has read, and which contains very few taxa.



`You are suggesting that a difference in the amount of statistical support for Ptyas as an outgroup between the two studies is evidence of polyphyly of Elaphe?'



Not just a difference, but, specifically, the correlation between increased in-group represenation and decreased support for the out-group's position.



`That is an unsupported interpretation of the available data. '



It's just common sense. Low outgroup support implies differences in relatedness between the out-group and different members of the in-group. If your in-group members are all closely related, out-group support should be high. If out-group support is low, probably the outgroup is either very closely related to all of the in-group taxa (which is argued against by the much higher outgroup support of Lopez and Maxson's study) or your in-group contains fairly divergent taxa, some of which are fairly closely related to the outgroup, and some of which aren't. It's not great evidence of polyphyly, but my main reason for mentioning it was that it's a more plausible explanation for the differences in out-group support than your offhand conclusion that it must indicate some problem with Utiger et al.'s data. Which, by the way, seems to be an `unsupported interpretation'.



`The only way Elaphe can be polyphyletic is if some of them form a clade with Ptyas to the exclusion of other species of Elaphe. he only way Elaphe can be polyphyletic is if some of them form a clade with Ptyas to the exclusion of other species of Elaphe. Neither Lopez and Maxson nor Utiger et al.'s data shows that. Tong et al.'s study also include Ptyas. Like the other two studies, theirs also show Ptyas outside of the Elaphe clade.'



This has already been addressed.



`You are obviously influenced by Utiger et al.'s single sentence on page 105, in which they claim that several authors "...concluded that Elaphe auct. as presently understood represents a large polyphyletic group." One of the papers they cite is that of Dowling et al. (1983). Dowling et al. do not include any of the Old World Elaphe species in their study. Therefore they have no data to show that Elaphe is polyphyletic; they are merely speculating'



Very good. So if you're willing to make the argument that an insufficient number of taxa can prevent conclusions about a genus as a whole here, why do you reject it in reference to Tong et al.'s and Lopez and Maxson's studies?



And I think that leaves us still with four papers concluding that Elaphe sensu lato is polyphyletic.



`Tong et al. (2002) also conclude that Dessauer (another paper cited by Utiger et al.) assumes that Elaphe is polyphyletic.'



Correct me if I'm wrong, but as far as I know we still don't know either what Tong et al.'s reasons for coming to this conclusion are, or even if Utiger et al. and Tong et al. are referring to the same paper.



` Further, Utiger et al. fail to cite Lopez and Maxson (1995), which clearly shows that Elaphe is a monophyletic group (paraphyletic if the Lampropeltini is excluded).'



This has already been addressed.



`It appears that Utiger is including studies that speculate on the polyphyly of Elaphe and at the same time overlooking those that refutes polyphyly. If that is the source of your "multiple independent studies concluding that Elaphe...is polyphyletic," then you have been misled by Utiger et al.'



Interestingly, Utiger et al. also cite Lenk et al. (mentioned elsewhere in this thread) but do not mention that Lenk et al. conclude that Elaphe sensu lato is polyphyletic. There doesn't appear to be a bias in regards to their citation on the matter.

Furthermore, which papers they've chosen to cite doesn't influence the validity of the papers they've cited. There are indeed multiple independent studies concluding that Elaphe sensu lato is polyphyletic, whether Utiger et al. may have failed to cite other studies (whether they support the opposite conclusion or not) or not.



`You may disagree all you want, but if your disagreement is unsupported by scientific evidence, then it is a meaningless disagreement.'



If we'll accept the converse implication, it would appear my disagreement is not meaningless.



Patrick Alexander

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