Reptile & Amphibian Forums

Is it Pantherophis guttatus slowinskii
or have they been given species status...Patherophis slowinskii.
This is really starting to get confusing

I thought it was Elaphe slowinskii, full species, not a subspecies of corn snake.

Also, I was unaware that Pantherophis is now deemed correct? Has this taken over Elaphe completely? Or just American??

At this point I really should have used Elaphe. I'm only trying to figure out what the most current studies, thinking and papers reflect.

This is a taxonomic proposal. Whether it is accepted or not will depend on whether the author who proposed it has a convincing argument. From what I hear, Burbrink's (2002) proposal to split the cornsnake into 3 species has not been well received by other systematists. His study, however, is very informative. It shows that emoryi is the oldest subspecies and that the other subspecies appear to have migrated to the east from the area now occupied by emoryi. That means the red coloration seen in E. g. guttata most probably evolved from a largely gray/brown colored animal like E. g. emoryi.

Quite obviously from this tree, the corn snakes share a single common ancestor. Burbrink is splitting the corn snakes NOT because they form a polyphyletic group, but he is splitting E. guttata because he is applying the so-called 'evolutionary species concept.' Burbrink writes: "The three lineages of E. guttata are each geographically confined to discrete areas, generally exclusive of one another, and most likely represent three distinct species"

Ernst Mayr (This is Biology) criticized this concept thusly:

'The evolutionary species concept has been promoted particularly by paleontologists who follow species through the time dimension. According to Simpson's (1961:153) definition, "An evolutionary species is a lineage (an ancestral-descendant lineage of populations) evolving separately from others and with its own unitary evolutionary role and tendencies." The main problem with this definition is that it applies equally to almost any isolated population. Also, a lineage is not a population. Furthermore, it side-steps the crucial question of what a "unitary role" is and why phyletic lines do not interbreed with one another. Finally, it actually fails in its objective, the delimitation of species taxa in the time dimension, because in a single gradually evolving phyletic lineage the evolutionary species concept does not permit one to determine at what point a new species begins and where it ends and which part of such a lineage has a "unitary role." The evolutionary species definition ignores the core of the species problem: the causation and maintenance of discontinuities among contemporary living species. It is rather an endeavor to demarcate taxa of fossil species, but it fails even in that endeavor.'

Indeed, Burbrink points out that there are some isolated populations '(i.e., specimens from Kentucky in the eastern partition and Colorado specimens in the western partition) [that] are separated from the large continuous partitions and may represent independent evolutionary lineages, [but] they will not be considered species here because they have not been appreciably examined morphologically or molecularly.'

Just as Mayr pointed out, any isolated population can be considered a lineage under the evolutionary species concept. But since a population is not a lineage, and since these "lineages" of corn snakes are not reproductively isolated from one another, most biologists who still subscribe to the almost universally accepted biological species concept will probably reject Burbrink's proposal.

`I thought it was Elaphe slowinskii, full species, not a subspecies of corn snake.'

Burbrink described it as a new species. Burbrink's full of it, though, so I doubt many other people will consider it a separate species. I'd guess most people will call it a subspecies.

`Also, I was unaware that Pantherophis is now deemed correct? Has this taken over Elaphe completely? Or just American??'

Utiger et al. (and there's a rather pointlessly-involved discussion of this somewhere below in the forum) assigned Elaphe obsoleta, Elaphe guttata (I don't remember offhand if they viewed emoryi or slowinskii as separate species, though I'd guess not), Elaphe vulpina, and Elaphe bairdi to Pantherophis. Elaphe flavirufa was assigned to the monotypic genus Pseudelaphe.

As has been mentioned in previous discussions, what's correct depends to some extent on who you ask. I think Pantherophis will be widely accepted, though.

Patrick Alexander

"Pantherophis" is a contrived genus, one of the many contrived genera that are morphologically indistinguishable from Elaphe. These genera are being recognized by Utiger et al. because they need many different genera to accomodate the pieces of a chopped up Elaphe, which is a paraphyletic genus. The cladists' destructive, impractical and scientifically untenable disqualification of paraphyletic groups from classifications has resulted in a constant need to recognize contrived, morphologically indistinguishable taxa. Since cladism is popular at present, and since many people simply follow the latest taxnomic proposals, Pantherophis will likely be "widely accepted."

Knowledgeable herpetologists, however, would most likely reject Utiger et al.'s proposal, just as they had rejected Frost and Etheridge's split of the Iguanidae and their lumping of the Agamidae and Chamaeleonidae. Frost and Etheridge's taxonomic proposal, once dubbed "fait accompli", has now been rejected by new taxonomic proposals. A return to the previous arrangement of 3 iguanian families is currently underway since Frost and Etheridge themselves have agreed to undo their lumping of the Agamidae and Chamaeleonidae. It is also just a matter of time before someone will publish a paper rejecting Utiger et al.'s destructive taxonomic proposal.

Unfortunately most people, including most biologists, are not steeped in the fine points of systematics or evolutionary biology. Therefore most people will simply follow the latest taxonomic proposals. For the foreseeable future, there will be taxonomic chaos, as many people will refer to the North American species of Elaphe as "Pantherophis" while others will continue to use the old genus Elaphe, since "Pantherophis," "Pseudelaphe," "Euprepriophis" and the other recently resurrected/erected genera cannot be distinguished morphologically from Elaphe.

A minority of one, so far as I can tell. Come back when you're interested in rational discussion.

Patrick Alexander

I believe that good philosophers fly alone, like eagles, and not in flocks like starlings. It is true that because eagles are rare birds they are little seen and less heard, while birds that fly like starlings fill the sky with shrieks and cries, and wherever they settle befoul the earth beneath them.---Galileo

I was in the minority in rejecting Frost and Etheridge's taxonomic rearrangement of the iguanian lizards, but I had plenty of good company. Veteran herpetologists like George Zug, James D. Lazell, and P. C. H. Pritchard rejected Frost and Etheridge's destructive proposal. I would much rather follow the flight paths of the eagles than to flock with the starlings, who will befoul the literature in the years to come by referring to the North American species of Elaphe as "Pantherophis."

Galileo says: "I decided to stand openly, alone, on the theater of the world, to bear witness to the sober truth. ...I wanted people to understand that Nature not only gave them eyes to see her works, but brains to make them capable of understanding them."

Indeed, good scientists are able to stand alone because they have the brains to understand Nature and the reasons behind the latest taxonomic proposals. Those who do not understand the rationale for the new proposals but who seek safety in numbers will simply flock with the starlings, adopt the new proposals blindly and befoul the literature with references to contrived genera that are morphologically indistinguishable from Elaphe.

You're neither, and my response to you in this thread is over.

Patrick Alexander

That may be so, but I can still determine for myself that "Pantherophis" is a contrived genus that is morphologically indistinguishable from Elaphe. I am able to do that because, unlike you or the cladists, I do not casually dismiss the wisdom of the great scientists past and present. Unlike you, I see no utility in recognizing the genus "Pantherophis" because with the present arrangement we have some assurance that Elaphe obsoleta is closely related to Elaphe scalaris, Elaphe quadrivirgata and Elaphe mandarina. If "Pantherophis" is recognized along with the other contrived genera resurrected/erected by Utiger et al., we would have no such assurance. As far as the nomenclature is concerned, we do not know if "Pantherophis" is really more closely related to Diadophis or to Thamnophis than it is to "Euprepiophis."

Could someone please enlighten me as to the basis for the proposed change to Pantherophis, So far all I can find are vituperative personal attacks with no discussion of the wherefore and why. Is the proposal based on morphology, sequencing behavior or what? While a relatively new addition to the herp world I am a familiar with cladistics and taxonomy in general.

>>Could someone please enlighten me as to the basis for the proposed change to Pantherophis, So far all I can find are vituperative personal attacks with no discussion of the wherefore and why. Is the proposal based on morphology, sequencing behavior or what? While a relatively new addition to the herp world I am a familiar with cladistics and taxonomy in general.

The basis is a paper by Utiger et al in Russian Journal of herpetology, in which the genus Elaphe was partitioned into multiple genera based on mtDNA sequences and adjunt morphological characters. Elaphe was shown to be paraphyletic with repect to the entire North American lampropeltine group, i.e., Lampropeltis, Pituophis, Arizona and N. America "Elaphe".

The non-monophyly of Elaphe was hardly a state secret, there have been other studies of the lampropeltinine group which have shown Elaphe to be non-monophyletic. Utiger et al. were the first to draw the nomenclatural consequences. E-mail me if you want a PDF of the paper.

The vituperative nature of the discussion here is largely due to one individual trying to drag us kicking and screaming back into the 1950's.

Hope this helps.

Cheers,

Wolfgang
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WW Home

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