You wrote:

Actually, Burbrink takes morphological disparity into account, and demonstrates its existence among the taxa he creates, in the splits of both guttata and obsoleta. He's just willing to accept very low amounts of morphological disparity if they agree with the cladogram.

Utiger et al. has already been addressed in this matter.



My response:

So, in your opinion, he will ignore morphological disparity if it does not jive with his cladogram? That is still ignoring morphological disparity to me.



I wrote:

`My interpretation is different. As one can see by the two new genera they coin, there isn't any good morphological character to distinguish

one genus from another since these characters are variable intragenerically or even intraspecifically.'



Your response:

This is incorrect. Two characters are given that unambiguously differentiate Orthriophis and Oreophis from each other, specifically:

precaudal vertebrae 193 in Oreophis, 222-272 in Orthriophis (yes, variable intragenerically, but there is no overlap, and thus no ambiguity in the differentiation of the genera) hemipenis cylindrical and with a basal hook for Oreophis, hemipenis biolobed and without a basal hook for Orthriophis.



My response:

Does the number of vertebrae distinguish Oreophis or Orthriophis from other species of Elaphe? Do the differences in hemipenial morphology, even if they are confirmed, justify the erecting (pun intended) of new genera?



I wrote:

`On the other hand, the taxa they recognize clearly are delimited from their consensus cladogram. Each major branch in that cladogram is

classified as a different genus. That is no different than Burbrink, who classifies each major branch in his analysis as a different species.'



Your response:

This is also incorrect. Though the weighted MP tree shows Zamensis as monophyletic, the consensus tree shows a polyphyletic Zamensis,

with Zamensis persicus apparently unrelated to the remaining Zamensis. Apart from the very close morphological resemblance between

Zamensis persicus and other Zamensis (particularly Z. lineatus and Z. longissimus, with which it was formerly considered conspecific), there

doesn't appear to be a compelling reason to conclude that these taxa should be congeneric. Yet Utiger et al. conclude they are congeneric.



My response:

You are correct about Zamensis not being a major branch in their consensus cladogram. You are incorrect that Zamensis is polyphyletic. All species of Zamensis do share a common ancestor, but this ancestor, at least according to the consensus cladogram, is also ancestral to all other genera they recognize, with the exception of "Euprepiophis." You have a very peculiar definitino of polyphyletic.



I wrote:

`It is true that there is no objective measure of morphological disparity. Darwinian taxa are indeed subjectively delimited. The alternative is far worse. The cladists, who have no guideline for delimiting taxa other than equal rank for sister taxa, are far more subjective. Kluge, for example, states that he can either recognize one, two or three genera given the particular topology of his cladogram. He finally decides that, for the sake of taxonomic efficiency, he will recognize but one genus for Charina bottae, Lichanura trivirgata and Calabaria reinhardtii. I submit that taxonomic efficiency is not an objective method for classifying organisms.'



Your response:

Any taxonomist could have recognized one, two, or three genera based on the available data. It's hardly a particular fault of cladism that it allows this.



My response:

That is not my point though.



You wrote:

I agree, though, that `taxonomic efficiency' is a very poor justification for any classification, particularly, in this case, because no greater efficiency is gained.



My response:

It can be a factor, especially if there is little morphological disparity among taxa within a monophyletic group. One can say that I support the recognition of a paraphyletic Elaphe partly because of taxonomic efficiency, but the primary reason remains the fact that there is no good reason in terms of morphological disparity to split it.



I wrote:

`In fact, it is far more subjective than if one relies on morphological disparity.'



Your response:

Kluge based his reassessment of the New World erycines entirely on morphology, though. He simply decided that the level of morphological disparity he found between Charina, Lichanaura, and Calabaria wasn't great enough to require a generic distinction. A Darwinian could have done the same.



My response:

There is no evidence that he ever considers morphological disparity in the classification of Charina, Lichanura and Calabaria. It is not present in his discussion. The only factor he considers is taxonomic efficiency. That is simply untenable.



I wrote:

`The first alternative of lumping all three into the same genus results in a morphologically heterogeneous taxon. The second alternative is to recognize three genera, meaning that Pan paniscus and Pan troglodytes would be classified in different genera, not very satisfactory. The third alternative is to recognize Pan and Homo as valid genera, the nearly universally accepted classification. Without any guidelines, the cladist is free to choose among any of these three equally valid alternatives. The Darwinians, however, are far more likely than not to choose the third alternative of recognizing 2 genera since they take morphological disparity into account.'



You wrote:

All three options are open to all taxonomists, though. I suspect that most cladists would be likely to recognize two genera, as well. I think the primary problem with Kluge's taxonomy isn't that it's cladistic, it's that it isn't very well done.



I wrote:

`The best alternative unfortunately, is one that is not available to the Hennigians, who are intolerant of paraphyletic taxa.'



You wrote:

And yet, as already discussed, an option that was available to Utiger et al. But, of course, that would've resulted in perpetuating a

morphologically heterogeneous taxon.



Patrick Alexander



My response:

If Elaphe is morphologically heterogeneous, then Utiger et al. have provided no evidence to support it. The fact that one has to look inside the lung to distinguish Old World Elaphe from New World Elaphe is stong evidence that your argument is baseless. The fact that Helfenberger, a junior author of Utiger et al., has to look inside the visceral organ for topographic differences among the species of Elaphe is further evidence that your claim of a heterogeneous Elaphe is also incorrect. There are some authors who, rightly or wrongly, argue that Bogertophis may not be morphologically disparate enough to warrant removal from Elaphe. That would contradict your unsupported assumption that Elaphe is a morphologically heterogeneous genus.

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