Reptile & Amphibian Forums

In what year did the taxonomy name change occur? I'm writing an article for our HERP newsletter and want to be acurate.
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Terry Norris, Keeper of the household Zoo

Hi,

well I had a quick look at the EMBL database (www.reptile-database.org)were right when recalling that it was Kluge (1993) who had placed this python in the genus Morelia. The reasoning why Kluge did so can be found in Kluge's proposal.

Cheers,
Wulf

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Python viridis SCHLEGEL 1872: 54
Chondropython azureus MEYER 1874: 134
Chondropython pulcher SAUVAGE 1878: 37
Chondropython viridis - BOULENGER 1893: 90
Chondropython viridis - DE ROOIJ 1917: 29
Chondropython viridis - STIMSON 1969
Morelia viridis - KLUGE 1993
Morelia viridis - MCDIARMID, CAMPBELL & TOURƒ 1999: 175
Chondropython viridis - COGGER 2000: 603
Morelia viridis - KIVIT & WISEMAN 2000
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http://www.leiopython.de - the white-lipped python site -
http://www.herpers-digest.com - herp related eBooks search -

Thanks.
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Terry Norris, Keeper of the household Zoo

>>Hi,
>>
>>well I had a quick look at the EMBL database (www.reptile-database.org)were right when recalling that it was Kluge (1993) who had placed this python in the genus Morelia. The reasoning why Kluge did so can be found in Kluge's proposal.

Yes he did, but he did it on the basis of 1) morphology and 2) cladistic classification philosophy.

The relationships among Old World pythons is poorly resolved, partly because DNA data is lacking for most species. Hence Kluge's morphological analysis is definitely not the final solution to the python classification problem. Further, Chondropython is morphologically and ecologically distinct from Morelia, and on this basis alone it deserves a genus of its own. Kluge ignores morphological differences between C. viridis and Morelia when he transferred Chondropython in Morelia (rather ironic since he uses morphology to determine relatedness). He did it because he thinks that Chondropython is derived from a species of Morelia and that Morelia sans C. viridis would be paraphyletic. Applying the same intolerance of paraphyletic taxa to, say, Pseudacris, one would have to transfer all species of Pseudacris back into Hyla, since Pseudacris is derived from a species of Hyla closely related to Hyla eximia. Recognizing Pseudacris would therefore render Hyla paraphyletic.

there are some rumors around about the resume of the Chondropython genus under which we'll find either the viridis that the carinata.

"Applying the same intolerance of paraphyletic taxa to, say, Pseudacris, one would have to transfer all species of Pseudacris back into Hyla, since Pseudacris is derived from a species of Hyla closely related to Hyla eximia. Recognizing Pseudacris would therefore render Hyla paraphyletic."

Is this example still relevant after the work by Faivovich et al, spliting up the former Hyla into a number of genera?
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Regards

Jan Grathwohl

HERPBREEDER.com - The Herpetological database

GECKOHOLICS.dk

>>"Applying the same intolerance of paraphyletic taxa to, say, Pseudacris, one would have to transfer all species of Pseudacris back into Hyla, since Pseudacris is derived from a species of Hyla closely related to Hyla eximia. Recognizing Pseudacris would therefore render Hyla paraphyletic."
>>
>>Is this example still relevant after the work by Faivovich et al, spliting up the former Hyla into a number of genera?
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>>Regards
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>>Jan Grathwohl

I haven't seen that paper, but I thought sooner or later Hyla is going to be split. It is just too large a genus. My objection to the cladists' intolerance of paraphyletic taxa is not contingent upon whether Hyla is split or not. It is simply impractical to keep splitting taxa because of paraphyly. Utiger et al., for example, split the genus Elaphe into a large number of morphologically undefinable genera that even snake experts cannot define. Doing so contributes nothing to our understanding of the relationship among the various subgroups of ratsnakes and in fact obscures the close relationship among them. Similarly, Kluge's lumping of Chondropython and Morelia obscures the rather unique habits and morphology of the green tree python. Returning back to Hyla, the type species of the genus is Hyla arborea, which is part of the crown group that includes almost all of the species of hylids native to the United States, and is closely related to the Hyla eximia group. This crown group is almost certainly derived from Hyla eximia. It would be interesting to see how one can possibly split Hyla without needing to severely restrict membership of this group to a handful of species. I will reserve judgment of the validity of this proposed split until I have read the paper but it appears that taxonomic chaos is upon us once again.

Hi

The work by Faivovich et al is available online at the American Museum of Natural History site - very interesting stuff

As for Elaphe - well i actually thing that personally that its quite strange to group eg. Elaphe scalaris together with Elaphe situla and Elaphe guttata - none of them seem to have anything in common (other than being colubrids). I have keept all three species and find it very weird that anybody has even considered grouping these together (especially scalaris is VERY unlike any other Elaphe)

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Regards

Jan Grathwohl

HERPBREEDER.com - The Herpetological database

GECKOHOLICS.dk

>>Hi
>>
>>The work by Faivovich et al is available online at the American Museum of Natural History site - very interesting stuff
>>

Thank you. Nevertheless, what some workers may do taxonomically with one taxon really has little effect on what should be done taxonomically with another group. For example, if one group is split on the basis of intolerance of paraphyly, it should have no effect on the validity of other paraphyletic groups. As some biologists have pointed out, paraphyly is the natural consequence of the process of evolution. Classifications that recognize paraphyletic groups are therefore natural. The intolerance of paraphyletic groups is therefore artificial and such intolerance has nothing to do with nature or evolution.

>>As for Elaphe - well i actually thing that personally that its quite strange to group eg. Elaphe scalaris together with Elaphe situla and Elaphe guttata - none of them seem to have anything in common (other than being colubrids). I have keept all three species and find it very weird that anybody has even considered grouping these together (especially scalaris is VERY unlike any other Elaphe)
>>
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>>Regards
>>
>>Jan Grathwohl

The problem with Elaphe is that it is a generalized group without too many morphological specializations. It is indeed difficult to define this group. Those species that are closely related to Elaphe but that have shown some morphological distinctness (e.g. Bogertophis, Arizona, Pituophis, Lampropeltis, Stilosoma et al.) have been removed from Elaphe and classified in other genera. The remaining species still retained in Elaphe are there because they haven't changed enough morphologically since they diverged from their common ancestors. Elaphe is thus a slowly evolving, paraphyletic group.

Some biologists are, as I pointed out, intolerant of paraphyletic groups because they agree with Hennig that paraphyletic groups should be disqualified from biological classifications. The problem with splitting a paraphyletic group like Elaphe is that the resulting genera cannot be morphologically distinguished from one another. Another problem is that the plethora of new genera really sheds no light on the close relationships among them and may mislead people into thinking that they are transferred to many different genera because they are not closely related. There is thus no gain in information by splitting Elaphe. All that we will "gain" is taxonomic chaos.

"Utiger et al., for example, split the genus Elaphe into a large number of morphologically undefinable genera that even snake experts cannot define."

You still stuck on that?

Come on, if you can't tell a Pantherophis from a Euprepriophis, you're blind.

"Doing so contributes nothing to our understanding of the relationship among the various subgroups of ratsnakes and in fact obscures the close relationship among them."

If all the segregate genera are closely related, no one's done any phylogenetic work to demonstrate it.

>>"Utiger et al., for example, split the genus Elaphe into a large number of morphologically undefinable genera that even snake experts cannot define."
>>
>>You still stuck on that?

If you mean I still find their taxonomic proposal untenable, then yes. Time has not changed that.

>>Come on, if you can't tell a Pantherophis from a Euprepriophis, you're blind.

Let's suppose that some people do not have the privilege of seeing these snakes in person. Can you tell these people the difference between "Pantherophis" and "Euprepriophis?" Can you describe the morphological differences between them? Can you tell us what new evolutionary changes have occurred in "Pantherophis" since these species have migrated from Eurasia to the United States and why these new evolutionary changes would justify classifying these species in "Pantherophis" instead of Elaphe? I submitted similar questions to some snake experts but so far I have not gotten any answers, and there is no effort to differentiate the many different genera within Utiger et al. These authors split the many species of Elaphe into a dozen or so genera without telling us how to distinguish these genera morphologically or even biochemically.

>>"Doing so contributes nothing to our understanding of the relationship among the various subgroups of ratsnakes and in fact obscures the close relationship among them."
>>
>>If all the segregate genera are closely related, no one's done any phylogenetic work to demonstrate it.

That is patently untrue. There are many biochemical and morphological studies which have demonstrated they are closely related to each other. The following paper (and references therein) is a good example:

Lopez, T.J., Maxson, L.R., 1995. Mitochondrial DNA Sequence Variation and Genetic Differentiation Among Colubrine Snakes (Reptilia, Colubridae, Colubrinae). Biochemical Systematics And Ecology 23(5):487-505

Yes, I for one agree. Despite the now widespread view that the viridis complex should be submerged into Morelia following Kluge's analysis, for the most part I still hold that this view is little more than uninformed, slavish idolatory. I have yet to be convinced that the distinct morphological radiation of a group of species that are each other's closest relatives - ie the genus Chondropython - should be synonymised with another morphologically distinct radiation of species - ie the genus Morelia....
Oh, and by the way, I still believe that Morelia carinata should not be placed within Chondropython just because of a few characters that may also be reasonably considered merely convergent with the viridis complex....

May the genus Chondropython live long and prosper !

Richard Wells

PS: Hi to Steno - I may have to travel to Europe soon so I will do my best to stop by and say hello. Things have been very hectic here but I hope all is well with your research.

Hello Richard,

>PS: Hi to Steno - I may have to travel to Europe soon so I will >do my best to stop by and say hello. Things have been very >hectic here but I hope all is well with your research.

well, if you are also going to visit Germany, let me know!

Cheers,
Wulf
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http://www.leiopython.de - the white-lipped python site -
http://www.herpers-digest.com - herp related eBooks search -

Hi Wulf,
I'll let you know when I'm leaving, so that you can put the coffee on ! Not sure of dates yet, but likely in the next few weeks. I may have to urgently take my daughter to a clinic in Switzerland so when things settle down I'll probably be in your backyard for quite a while...perhaps we can undertake some field work...

Kind Regards

Richard Wells

You know Dr.Wells my e-mail address...I hope you'll keep in touch with me just to meet me and have a lunch together maybe in Rome or where you prefer.
Cheers
Stefano

Look forward to catching up - Rome would be nice this time of the year...

Best Wishes to you

Richard Wells

>>Yes, I for one agree. Despite the now widespread view that the viridis complex should be submerged into Morelia following Kluge's analysis, for the most part I still hold that this view is little more than uninformed, slavish idolatory. I have yet to be convinced that the distinct morphological radiation of a group of species that are each other's closest relatives - ie the genus Chondropython - should be synonymised with another morphologically distinct radiation of species - ie the genus Morelia....

You have to understand the fact that although Kluge used similarities in morphological characters to group species and to elucidate relationships among the species he studied, he did not base his classification of these same species on the morphological differences or similarities between them. What Kluge and other cladists are trying to figure out first and foremost is a tree, or a branching diagram of genealogical relationships. After the tree is obtained, it is then decided how best to classify organisms based on the arrangement of that tree, using the guiding principle of the cladists, which they call the principle of monophyly. WW explains how it works on his web site the last time I visited. Briefly stated, cladists like Kluge and others do not want to split the tree in such a way that a taxon will consist of anything other than a single ancestor and all of its descendants. No matter how morphologically different one of the descendants of this common ancestor is, it must remain within the taxon if removing it results in a paraphyletic parental group. The alternative is to recognize a distinctive descendant as a distinct taxon and then split the remainder of the parental group into as many groups as necessary to make sure that each and every one of these groups consist of a single ancestor and all of its descendants.

Any group that is missing even one of the descendants of the common ancestor is termed "paraphyletic" and paraphyletic taxa are not recognized by cladists. Thus the principle of monophyly has often resulted in either excessive lumping or excessive splitting. In my experience, Kluge tends to be a lumper, so he lumped Morelia and Chondropython in the same genus. Other taxnomists, using the same principle as Kluge, may have a tendency to split. The splitters therefore would probably have split Morelia into several different genera, each of which may differ little from one another. A good example of excessive splitting would be Utiger's split of Elaphe into many morphologically indistinguishable genera formerly placed in Elaphe.

>>Oh, and by the way, I still believe that Morelia carinata should not be placed within Chondropython just because of a few characters that may also be reasonably considered merely convergent with the viridis complex....

Perhaps a good way to determine that question would be the use of molecular data. Often morphological features are subject to convergence, far more so than molecular characters in general, although there are exceptions to that general rule. Until molecular data is available, any attempt to reclassify the pythons on the basis of morphology would probably only be a short term solution that is bound to be overturned by future molecular studies.