Reptile & Amphibian Forums

I think at the very least we can say that, for now at least, the eastern indigo is considered it's own species.

The follwoing is a quote from Paul Moler of the Florida Fish & Wildlife Conservation Commission in an email to me when I asked his thoughts.

"SSAR Committee on Standard English and Scientific Names now recognizes it as a separate species. Given that no natural contact occurs between couperi and other Drymarchon, the decision regarding their specific status is as much philosophical as biological. The SSAR list adds the caveat: "Whether the diagnosibility of this taxon holds up against rigorous scrutiny across the distribution of Drymarchon is open to testing."

In any event, for the moment at least, consensus favors recognition of D. couperi. As for other subspecies of D. corais, I am too unfamiliar with the literature to comment."

Paul

So we are now calling them Drymarchon couperi? Personally, I think in some ways it makes a lot of sense since we don't, to my best knowledge, have any indications of natural hybridization taking place with other "corais". I wonder if I should be changing my signage at the wildlife center! Rob

might be a bad question but what natural or unnatural causes would have separated eastern and texas indigos over the years in their ranges(if they did at one time overlap)? lack of suitable habitat? i notice the rest of the indigo famly overlaps although i heard the yellowtails don't interbreed with the blacktails. steve h

I think it's safe to assume that the ranges did at one time overlap or at least meet. I would think that all of the species/subspecies of Drymarchon evolved from one common ancestor, each subspecies evolving to adapt to it's particular environment. I would think that the Eastern Indigo and the Texas Indigo ranges have been separated for quite a long time and were probably different forms (subspecies) when the separation occurred. It would make sense to me that the overlap between these two was in the area of what is now Louisiana and probably the barrier would have been the Mississippi River. I would think that the extirpation of the species from Louisiana, East Texas and Western Mississippi would have been a natural event due to changing climate, naturally sparse populations in those areas and possibly other natural events such as hurricanes, flooding, etc.

Just my thoughts...could be all wet.

I agree with "oldherper" a snake like Drymarchon that is at the northern limit of its range ( historically just getting into the southern portion of South Carolina) mating in the fall and not really hibernating ( reported active on sunny winter days) would be very sensitive to even a small climate change. I know the panhandle of Florida has a interesting geologic history & guess that whole section right along the Gulf would have been subject to all kinds of periodical habitat changes.

Once a upon a time an introdution of large numbers of indigos was tried on an island in the gulf.

The island had good habitat, tortoises, diamondbacks...seemed ideal.

It also had one other thing: Wild pigs.
The indigos made it right up to the point where the island suffered heavy storms and much of the island's freshwater was infiltrated with oceanwater.

This caused many of the islands critter to congrate in the few remaining areas of fresh water...where they were easy pickin's for the pigs.

The indigos never recovered.

Storms along the gulf...predation from ferile animals...habitat fragmentation along the more populous areas around the coast...etc, could have all eventually led to the demise of the indigos here, and cut off the 2 populations.

Do a herp a favor:
Have a pig roast.

I don't buy into the whole evolution thing but, I do agree with a lot of what's been put forward here, easterns & texans surely did inter-grade & for this reason, I have some degree of difficulty with couperi being elevated to a full species. Correct me if i'm wrong but, doesn't inter-gradation occur only at the sub-species level & not at the genus or species level?

Hog roast at Deans house! Consider this my RSVP When should we ALL show up?

Eric

i agree with you eric(about the evolution thing)but it seems like animals can change and adapt to their surroundigs(color, size,etc. if possible). if not they disappear. steve h

But that's what change over time is. (evolution)

The "e" word is not a dirty word.
It's happening now, as it always has.

The proof is everywhere.

Call it change over time, natural selection, evolution...
it's all the same idea.

The animals that are best suited for their environment survive and pass along their genetic traits...over time...that leads to dramatic change ....i.e. evolution.

I'm not sure why it's such a debated topic.
It is what it is. It doesn't prove or disprove anyone's religious beliefs.

I have my beliefs on the origin of species, you have yours...but I think evolution is separate from religion...or what "started the process". Evolution is. Period.

Eric you are invited to my house for ham sandwiches and pork roast whether you believe in evolution or not.

I have had some wonderful (and some times heated) dialogue with colleagues in the herp world on this subject. Although I am not a follower of Darwin, there is no doubt that evolution in the "micro evolutionary" context is absolutely 100% scientifically true and is happening in this present day and age. We see it everywhere (i.e. many island forms of Anolis) but the real question is whether these small changes due to the environment truly lead to animals changing from one kind into a distinctly other kind...that is the question we all want to see answered (and the "mechanism" by which they change....I have my own ideas but they are just that, ideas which unfortunately, cannot be proven by today's scientific inquiry nor can devout evolutionists truly prove their's by use the strict definition of science). We all have the exact same "evidence" but it is how we interpret this evidence or data that dilineates our belief systems. This is very complex and probably outside the scope of this forum so I would be happy to share my beliefs with anyone outside of this forum. This is actually great fun and I agree with Dean in that there is no reason that religion, science and the many ideas floating around need to be in conflict with one another. We are all striving to find the truth and even though I know in my heart I have found it, I will continue to enjoy learning more about it while listening to those whose beliefs are in direct "conflict" of mine. The problem is that people get so defensive about their beliefs that they become obstinant to anyone who doesn't share that belief. I have colleagues on the far ends of the spectrum and I have great respect for both. Rob

Very well said Rob!
This is too great a place to let our differences screw it up!

Eric

i have no problem with people saying animals evolved,adapted, changed over time. it make sense but i personally think that a Creator has given them the ability to do it. i in no way want to put someone elses beliefs down(religious or other). this is how we learn. steveh

Eric,
When I said "evolved". I did not mean that they started out as an armadillo in Mexico, spread out, and evolved into Indigo Snakes and Cribos. I wasn't speculating on how the original Drymarchon type originated. What I meant was that I think in the beginning there was one species type of Drymarchon that ultimately extended it's range to cover from the Coastal Carolinas to Southern Brazil. Ultimately the members of this population began to change (evolve) to suit their specific environments resulting in the subspecies we have now. Some were cut off from their brethren by natural phenomenon, and in those cases interbreeding stopped causing a divergent evolution resulting in populations that looked less and less like each other (ie Texans and Easterns).

Intergradation takes place between overlapping subspecies. Interspecific hybridizing can and does occur, but it's not the norm. Eastern Indigos and Texas Indigos never naturally intergrade because their ranges are so far separated. Texas Indigos do intergrade naturally with other members of the proposed D.melanurus group. The recommendation to afford D.c.couperi full species status is based partly on this and on marked differences in scalation which is always consistent, among other things.