Reptile & Amphibian Forums

I was wondering...
with the new classifications I was wanting to clear a few things up

Bairds rat snake: Now Pantherophis bairdi?
Yellow rat: now Panterophis quadrivittata?
everglades rat: now Pantherophis rossalini?
spelling on that last one?
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Corn snakes and rat snakes..No one can have just one.
"resistance is futile"
Jimmy (draybar)

In fact, this is a very good question. My sense is that the change of genera to Pantherophis is catching on gradually among herpers, but there will always be traditionalists that will consider them Elaphes. As for the affording of individual species status to Yellow/Everglades Rat snakes, I'd be surprised if this change is accepted. IMO, there is enough intergradation between these varieties (and the Black Rat) to suggest that they all would have to remain subspecies of P. obsoleta. But I'm not an expert on taxonomy, and I could be completely wrong.

I vaguely recall from a post here last year that there was a move to divide North American Pantherophis into three basic species, based largely on geography. A scan of the 2003 forum archives may turn up that thread. I'll defer to someone more knowledgeable (or with a better memory) on the details.
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MichaelB

According to the mtDNA evidence in the latest big study, a bairdi and a lindheimeri are closer than a lindheimeri and for instance an obsoleta from the carolinas. Does that mean bairdi is an obsoleta subspecies or does it mean that obsoleta should be broken up like Burbrink did into eastern, central and western geographic species rather than subspecies by color and pattern? I certainly don't know, but it is an interesting question.
Regards
John

I have read some of the papers and the arguments pro and con. This argument will go on for quite some time.

First, the paper that suggests that obsoleta be divided only by geographic region and not by color and pattern uses Elaphe as the name of its genus.

Evolution, 54(6), 2000, pp. 2107–2118
MITOCHONDRIAL DNA PHYLOGEOGRAPHY OF THE POLYTYPIC NORTH
AMERICAN RAT SNAKE (ELAPHE OBSOLETA): A CRITIQUE OF THE
SUBSPECIES CONCEPT
FRANK T. BURBRINK,1 ROBIN LAWSON,2 AND JOSEPH B. SLOWINSKI3
1Museum of Natural Science and Department of Biology, 119 Foster Hall, Louisiana State University,
Baton Rouge, Louisiana 70803
E-mail: fburbri@unix1.sncc.lsu.edu
2Osher Foundation Laboratory for Molecular Systematics and Department of Herpetology, California Academy of Sciences,
Golden Gate Park, San Francisco, California 94118
E-mail: rlawson@mail.calacademy.org
3Department of Herpetology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118
E-mail: jslowins@calacademy.org
Abstract. Subspecies have been considered artificial subdivisions of species, pattern classes, or incipient species.
However, with more data and modern phylogenetic techniques, some subspecies may be found to represent true
species. Mitochondrial DNA analysis of the polytypic snake, Elaphe obsoleta, yields well-supported clades that do
not conform to any of the currently accepted subspecies. Complete nucleotide sequences of the cytochrome b gene
and the mitochondrial control region produced robust maximum-parsimony and maximum-likelihood trees that do not
differ statistically. Both trees were significantly shorter than a most parsimonious tree in which each subspecies was
constrained to be monophyletic. Thus, the subspecies of E. obsoleta do not represent distinct genetic lineages. Instead,
the evidence points to three well-supported mitochondrial DNA clades confined to particular geographic areas in the
eastern United States. This research underscores the potential problems of recognizing subspecies based on one or a
few characters.
Key words. Control region 1, cytochrome b, Elaphe obsoleta, evolutionary biology, maximum likelihood, maximum
parsimony, mitochondrial DNA, species, subspecies.
Received November 12, 1999. Accepted May 18, 2000.

There are also arguments out there that show that mtDNA evidence is not enough to make such determinations.

Evolution, 56(3), 2002, pp. 527–545
DIVERGENCE OF MITOCHONDRIAL DNA IS NOT CORROBORATED BY NUCLEAR
DNA, MORPHOLOGY, OR BEHAVIOR IN DROSOPHILA SIMULANS
J. WILLIAM O. BALLARD,1,2 BARRY CHERNOFF,3 AND AVIS C. JAMES1
1Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242
2E-mail: bill-ballard@uiowa.edu
3Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605-2496
Abstract. We ask whether the observed mitochondrial DNA (mtDNA) population subdivision of Drosophila simulans
is indicative of organismal structure or of specific processes acting on the mitochondrial genome. Factors either
intrinsic or extrinsic to the host genome may influence the evolutionary dynamics of mtDNA. Potential intrinsic factors
include adaptation of the mitochondrial genome and of nucleomitochondrial gene complexes specific to the local
environment. An extrinsic force that has been shown to influence mtDNA evolution in invertebrates is the bacterial
endosymbiont Wolbachia. Evidence presented in this study suggests that mtDNA is not a good indicator of organismal
subdivision in D. simulans. Furthermore, there is no evidence to suggest that Wolbachia causes any reduction in nuclear
gene flow in this species. The observed differentiation in mtDNA is not corroborated by data from NADH: ubiquinone
reductase 75kD subunit precursor or the Alcohol dehydrogenase-related loci, from the shape or size of the male genital
arch, or from assortative premating behavior. We discuss these results in relation to a mitochondrial genetic species
concept and the potential for Wolbachia-induced incompatibility to be a mechanism of speciation in insects. We
conclude with an iterated appeal to include phylogenetic and statistical tests of neutrality as a supplement to phylogenetic
and population genetic analyses when using mtDNA as an evolutionary marker.
Key words. Behavior, Drosophila simulans, mitochondrial variability, morphometrics, species concepts, Wolbachia.
Received July 6, 2001. Accepted November 12, 2001.

None of this is a done deal. Hobbyists like myself will just have to keep reading and let the experts fight it out among themselves.

Great question, but no easy answers.

The question seems to me to be more of ..Is all this constructive or even necessary?

Without even looking at DNA for example you could separate P. guttata into 3 more subspecies.

Besides P.g.slowinski and rossalleni, you could further divide P.g.guttata into say;

P.g.okeetee. For Okeetee phase

P.g.miamiensis For Miami phase

P.g.Aneryensis For the very distinct wild population of Natural Anerys

Each of these forms is capable of reproducing it's charactoristics to future generations so what makes them any different from the other sbsps?

While your at it, we could split Mexican Bairds from Texas (they certainly are different enough).

If we go with the minute reclassification of snakes that are so subtly different, what happens when we go for species that are highly variable (even within the same litter)?

I think before there is more splitting we need to nail down a DEFINITION OF WHAT IS A SPECIES AND WHAT (IF AT ALL) IS A SUBSPECIES). Also a clear definition of what DNA factors are considered to be compelling enough to set a standard definition of this. And then get it into print so poor old laymen like myself can make sense of the mess.

Frank
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"The luxury of not getting involved departed with the last lifeboat Skipper..."

Hey, Frank.

Looks like we were posting at about the same time. I hadn't read yours here, or down below in reference to the rarest ratsnake. Also, in a moment of confusion I used your name in my first post here (I was refering to Elaphefan). Sorry about that.

Back to your question, "Is all this constructive or even necessary?" I would say yes. It is science even if it isn't exact science. I would like to know as much as possible about the species I work with, so struggling with ideas that make me learn more help me understand the snakes better. Should we make 'emoryi' and 'guttata' separate species?...great question. Should we make more or less subspecies w/i guttata?...another good question. I like discussing these possibilities.

TC

Jimmy,

I agree with the others mostly, and it's a great question, because it's exactly what's going on with all us amateurs and the real herpetologists. We each have to make our own decisions and also watch the literature to see what's happening in scientific circles. Nice work, Frank, btw, to post the references to some of the changes.

I've been struggling with some of these questions for years because of my interests in the hobby. Whether to accept changes, or refer to old nomenclature. I've mostly switched back and forth until I felt somewhat comfortable with a decision. It can be very confusing.

When Burbrink published his findings on Elaphe obsoleta, the changes in the genus name had not occured, yet. I don't believe he had studied the Old World ratsnakes much. So, he naturally used the genus name, Elaphe. Since then, new genetic findings have proposed generic changes, and thus all the new genus names, to put it rather simply. Although I fumble a lot with the ideas too, and I'm certainly no genetic scientist, I do like the new generic changes, because I think they show relationships better between the different Old and New World ratsnakes. Many of the New World species fit into the new genus, Pantherophis, which I agree with, because the Elaphe of the Old World are more closely related, and should be differentiated from New World forms, imho.

All these changes will be dealt with in time. Sometimes they get accepted and sometimes not. Right now, I think the genus Pantherophis is being well accepted, and I'm going along with this because I really like the change and the name. The more it gets used in the literature, the better established it becomes. Now, the changes Burbrink made in obsoleta have not been well accepted, imo, and I personally don't like them, so I haven't been using them. They may be accepted in the literature eventually, however, but we'll see on that. Hence, I would call the black ratsnake, Pantherophis obsoleta obsoleta, not changing the species/subspecies idea, but changing the genus name.

Hope I haven't created any additional confusion. It's just great subject matter and deserves to be discussed by anyone who wants to. BTW, another snake that you mentioned would be in Pantherophis too, P. bairdi. In my take on the matter, Pantherophis also includes...P. guttata, P. vulpina, and P. gloydi. Sorry for being long winded. I'll be going back to work next week, so won't have time for these extensive posts, and you guys will have a break from all the reading for a few months..LOL.

Cheers....TC

Deciding factor for me: Elaphe, is shorter and easier to spell.
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Lloyd Heilbrunn

Palm Beach Gardens, Fl.

I have found that I am a splitter in large part. I've many articles proposing the changing of genera [ie. Elaphe guttata - Pantherophis guttata ]. In particular I paid close attention to the Utiger treatment of Elaphe taeniura friesei - the Taiwan Beauty Snake. I have a pair and can see easily how when you start looking at them you see differences between them and the average Elaphe, be it Elaphe guttata or obsoleta or one of the ancestral Old World Elaphe.

However, I don't know enough about genetics and taxonomy to unequivocably accept a taxonomic change. Instead, I've deferred to the EMBL Reptile Database
[ http://www.embl-heidelberg.de/~uetz/LivingReptiles.html ], to monitor whether recent taxonomic changes have been accepted by the scientific community at large. Read up on the EMBL page and you'll see how they determine which changes to accept and put forward.

Another resource I look at is the species holdings section of ISIS.org [ http://www.isis.org/ ], which is what shows the numbers of animals of any given species held at zoos throughout the world. Because of extensive record keeping, zoos are some of the last holdouts to accept taxonomic changes, so if the zoos have accepted a change you can usually be sure the scientific community at large has as well.

An interesting point brought up by this is that for instance, AZA [ American Zoo and Aquarium Association ] lists the Dumeril's Ground Boa as Boa dumerili, and the other subspecies as Boa madagascariensis, whilst both the EMBL and ISIS still list it as Acrantophis spp. Hmm... the same goes for Sanzinia madagascariensis, the Madagascar Tree Boa, which AZA lists as Boa manditra [ "manditra" is apparently Malagasy for Tree Boa ], while again, EMBL and ISIS are adhering to the older taxonomy of Sanzinia.

An interesting point in the Boa manditra/Boa dumerili question is that in the Dorling Kindersley handbook of Reptiles and Amphibians written by Mark O'Shea and Tim Halliday, they use the Boa manditra/Boa dumerili taxonomy - the book was published 2001 2002. The EMBL site shows that the proposal was made and it would appear a later paper gave evidence for reverting back to Acrantophis/Sanzinia.

It's all so confusing, isn't it? While I'd like to split where applicable, one finds that if the changes are not being accepted widely it's really hard to keep calling your corn snake a Pantherophis, and your Taiwans Orthriophis - besides which, the whole point of trinomial nomenclature was to have a common language that all researchers could use and if we keep proposing changes that are not widely accepted, we muddy the waters. Sheesh!
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Matt Campbell
Animal Keeper, Small Mammal/Reptile House
Lincoln Park Zoo Chicago, Illinois

Assistant Curator
Wildlife Discovery Center at Elawa Farm
Lake Forest, Illinois

>>I was wondering...
>>with the new classifications I was wanting to clear a few things up
>>
>>Bairds rat snake: Now Pantherophis bairdi?
>>Yellow rat: now Panterophis quadrivittata?
>>everglades rat: now Pantherophis rossalini?
>>spelling on that last one?
>>-----

Now let me explain the reason for my question.
I started keeping rat snakes and corn snakes as a hobby and for fun.
These are still my reasons but due to the increasing number of acquisitions, hatchlings and potential sales of non-keepers I have to get the legal permits before I loose everything. I sure don't want that to happen.
When you have one or two this isn't a problem but when you go from several snakes to over thirty keepers in just a few months this can get away from you quickly. Especially when you look at the potential offspring next year..whew.
So, anyway I am composing a list of all of my snakes and where I got them and I read that they need to be listed by their scientific or "latin" names. I thought I better find out which I should use.
Now, just a little imput on the change to Pantherophis for the New World rats. I personally agree with the change. I just don't see how they can continue to be classified with the Old World Elaphe.
My feelings or opinion on the Emoryi or Great Plains rat..
As the Corn snake was Elaphe guttata guttata and the Emoryi was listed as sub specific Elaphe g. emoryi, I would like to see it continued as subspecific to the corn.
Pantherophis guttata and Panterhophis g. emoryi.
Just what I would like to see....oh well.

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Corn snakes and rat snakes..No one can have just one.
"resistance is futile"
Jimmy (draybar)

Jimmy, you should have said you wanted to list them for the authorities..haha.

This is how I would do it....

Black ratsnake = Pantherophis (Elaphe) obsoleta obsoleta

I'd list the old genus name in parenthesis because many authorities may not recognize the new name.

Terry

>>Jimmy, you should have said you wanted to list them for the authorities..haha.
>>
>>This is how I would do it....
>>
>>Black ratsnake = Pantherophis (Elaphe) obsoleta obsoleta
>>
>>I'd list the old genus name in parenthesis because many authorities may not recognize the new name.
>>
>>Terry
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Corn snakes and rat snakes..No one can have just one.
"resistance is futile"
Jimmy (draybar)