Patrick wrote:



"Nope, the grouping of Euprepriophis with the other taxa studied rather than Ptyas is poorly supported. And Ptyas is the outgroup--it's supposed to be distantly related to all of the taxa involved, so a poor support for its outgroup status is particularly damning."



Tong et al. find strong statistical support both for Ptyas as an outgroup to Elaphe and for Elaphe mandarina as the basal most member of the Elaphe clade. Lopez and Maxson have a similar finding regarding Ptyas as the outgroup. Neither Tong et al. nor Lopez and Maxson included Senticolis in their analysis. The fact that Utiger et al. included Senticolis in their analysis may have weakened the statistical support for their tree near the base, since Senticolis may very well be a racer and an outgroup to Ptyas plus Elaphe. Senticolis plus Elaphe may well be a polyphyletic group. But since Senticolis triaspis has already been shown to be morphologically and genetically distant from any known species of Elaphe, there is no reason to transfer it back to Elaphe. Elaphe (sans Senticolis) is not polyphyletic. If Utiger et al. redo their analysis without Senticolis, they may find much better statistical support for their tree.



Utiger et al. apparently had the preconception that Senticolis is part of the American ratsnake clade and they chose a cladogram that reflects such a relationship accordingly, resulting in poorer support for Ptyas as the outgroup than in other studies of colubrid relationships, such as those of Tong et al. and Lopez and Maxson.

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