In this latest post, WW (aka Dr. Wolfgang Wüster) is claiming alternatively that Elaphe is "non-monophyletic" and paraphyletic. In an earlier post, a link to which I have provided, Dr. Wüster actually claimed that Elaphe is "polyphyletic." It appears that he has withdrawn his earlier claim of Elaphe polyphyly, ostensibly because evidence presented in the earlier debates on the evolutionary relationships among the ratsnakes (admittedly acrimonious at times because of differing, mutually incompatible ideologies) may have persuaded Dr. Wüster that Elaphe is in fact not polyphyletic, albeit paraphyletic or "non-monophyletic."

It is no secret that Dr. Wüster is adhering to Hennig's definition of "monophyletic," which requires that a group consists of a single ancestor and all of the descendants of this ancestor to be considered "monophyletic." However, scientists other than Hennig and his followers have always used the term monophyletic differently than the Hennigians or cladists. It is nearly universally accepted, for example, since the discovery of the fist known bird Archaeopteryx, that birds are the descendants of reptiles, since Archaeopteryx has so many reptilian features that there is no doubt about an evolutionary link between these two groups. Because birds and reptiles have been classified in different classes (Reptilia and Aves) prior to the discovery of Archaeopteryx, Reptilia is now "paraphyletic" or "non-monophyletic" according to the Hennigians or cladists since it is obvious that Reptilia does not include all descendants of its common ancestor. If so, then why did scientists, who were living at the time Archaeopteryx was discovered, not disqualify Reptilia because it is "paraphyletic" and thus "non-monophyletic?"

The reason is quite simple, the term paraphyletic simply did not exist. Nobody other than Hennig has considered Reptilia an invalid taxon because it is "paraphyletic" or "non-monophyletic"; the monophyly of Reptilia has never been in doubt. Indeed Reptilia (without including the birds) is still considered monophyletic by most scientists, as it has been since the publication of Darwin's Origin of Species. Why, then, are there prposals to dismantle "paraphyletic" taxa such as Elaphe? It is because a new generation of taxonomists have decided to depart from tradition and follow the idiosyncratic taxonomic conventions dictated to them by the German scientist Willi Hennig, who first introduced his methodology in the 1950's.

The Hennigians are of course entitled to their believes that so-called paraphyletic taxa, such as Elaphe and Reptilia are “non-monophyletic” and thus not acceptable. However, other scientists do not share their believes. The Darwinians, and in fact Darwin himself, consider so-called “paraphyletic” groups to be monophyletic, since the members of such groups are all descended from a single common ancestor. Darwinians do not reject taxa because they are paraphyletic, since these taxa are monophyletic to the Darwinians.

Clearly there are two different definitions of monophlyetic and they stem from the fact that there are at least two different schools of taxonomy (the Hennigians or cladists and the Darwinians). Do the Hennigians then have the right to impose their believes on the Darwinians and also the rest of the scientific community by requiring us to accept their taxonomic proposals?

My answer to that question is no, the Hennigians do not have that right. The well known evolutionary biologist Dr. Ernst Mayr of Harvard University, who is a Darwinian, concurs. Dr. Mayr sums up the disagreement between the Hennigians and Darwinians quite nicely in the following passage from his book "Principles of Systematic Zoology (2nd ed.)"

‘Hennig developed the cladistic method on the basis of the assumption that new species originate by the splitting of a stem species into two daughter species. hence on the principle of dichotomy: The parental species disappears with the birth of the two daughter species. He saw the origin of new higher taxa in an equivalent manner as a dichotomous process. Much research of the last 50 years has indicated, however, that budding is a far more frequent way of originating new taxa than is splitting. When a new species originates by means of peripatric speciation, this has no effect on the parental species from which the neospecies has budded off. However, by Hennig's criteria, a species which has given rise to a new species by budding thereby becomes paraphyletic and has to be removed from the classification, even though it has not been affected by the budding event. The same alignment pertains to higher taxa, most of which evidently originated by the budding off of an enterprising new species that was successful in a new niche or adaptive zone. The parental taxon continued to flourish unchanged in its traditional niche, but it has become paraphyletic by cladistic definition and must be excluded from the classification. It is now fully evident that the proposal to disqualify paraphyletic groups from recognition in classifications is not only impractical and destructive but scientifically untenable.'

Dr. Wüster is quite correct to point out that there has been a lot of resistance (“kicking and screaming”) to proposed taxonomic changes based on ideological disagreements. Since it is the cladists, or Hennigians, who are proposing that paraphyletic taxa be dismantled in many cases, the resistance actually comes from the Darwinians, who believe that paraphyletic taxa are in fact monophyletic and therefore there is no reason to dismantle them. The Darwinians simply do not want the cladists to impose Hennig’s believes on them since the Darwinians do not share the same believes.

In sum, Utiger et al. are proposing that the genus Elaphe, which is “paraphyletic” (and which has been known to be “paraphyletic” for over a quarter of a century, if not much longer) be dismantled and the species therein be transferred to a number of genera that have been relegated to the synonymy of Elaphe for almost a century in many cases because these genera cannot be distinguished from Elaphe morphologically. Utiger et al. proffered no evidence that the ratsnakes that have been traditionally placed in the genus Elaphe is polyphyletic. Nevertheless, Utiger et al. is entitled to present their taxonomic proposal, which of course can be evaluated by any scientist and either accepted or rejected. I only want to point out the reason why they are proposing these changes. The reason they are proposing these changes is because of their ideological intolerance of paraphyletic taxa. Those who share their philosophy and intolerance may well adopt the proposed changes. Those who do not know anything about systematics and/or taxonomy will likely follow the lead of others blindly. Those who do not share Utiger et al.’s ideology will likely ignore or reject the proposed changes IF they know why Utiger et al. are proposing the changes.

Finally, I thank WW, or Dr. Wolfgang Wüster, for articulating the reason why Elaphe is being splintered by Utiger et al. Utiger et al. is not dismantling Elaphe because it is polyphyletic, a claim that Dr. Wüster has apparently abandoned, but because it is "paraphyletic." Is the new arrangement an improvement over the old? Only if you think that replacing paraphyletic taxa with contrived taxa that are impossible to consistently define represents scientific progress.
Earlier message by WW

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