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Crotalus Horridus?
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by snakeguy101 on October 15, 2007
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what are your views of the division of this species, i am writing an article for my website and wanted to know some more opinions. your answers may be quoted unless you otherwise specify, thanks.
~Chris~
www.snakeguy101.com
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RE: Crotalus Horridus?
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by Chance on October 15, 2007
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I'll probably step on some toes here, but fortunately, science is not decided by majority opinion. Empirical evidence rules the day, and to the most current knowledge on the mtDNA of Crotalus horridus across its entire range, there is no justification for subspeciation. I'm not a die-hard though like many others: if new research finds that the previous information was incorrect, I will adjust my views accordingly. Until then, canebrake is just a nick name for the southerly variant of C. horridus.
-Chance
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RE: Crotalus Horridus?
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by Peter84Jenkins on October 15, 2007
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I am sorry but I have a problem beleiving that mitochondrial DNA is the almighty answer to correctly classifying living things. Sure DNA can tell a desperate, promiscuous 18 year old girl who the real daddy is but it’s not the ultimate end all answer to the linnean system. If that was the case then we humans should consider Apes Homo sapiens based on subtle DNA similarities. There are very few genomes separating us from our more primitive, poop throwing uncles. Carl Linneaus didn’t have the luxury of DNA when he created his primitive classification system but he did have enough forethought and true scientific intuition to classify organisms based on a number of traits. Canebrakes are physically and geographically different from the “traditional” timbers. They are much larger, the head is shaped different, patterns can be similar but for the most part different, they are on a different reproductive cycle, vastly different habitats with some exceptions. Mt DNA is a great tool but I am skeptical of its use in taxonomy. But these are my own observations and I am not claiming them to be based on the personal achievement of a Phd in genetics only personal research (possibly a result of my stubborn inability to conform, but instead form my own opinion.) I don’t doubt sound scientific research. There was a time when Aristotle was accused of blasphemy for doubting common beliefs. Any way I will probably catch hell from all the mt DNA followers so I will stop now.
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RE: Crotalus Horridus?
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by Littlesnakedaddy on October 15, 2007
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Why not just search the forum?
This has been the topic of many threads.
Should have been here when Bobby, Chad and Karl went at it.
http://www.venomousreptiles.org/libraries/showfilepage/4344
LSD
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RE: Crotalus Horridus?
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by Chris_Harper on October 15, 2007
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Well, there's two kinds of them suckers. You got your Timber rattlesnake, Crotalus horridus. And you got your Canebrake rattlesnake, Crotalus horridus.
If you say "canebrake", we know what you mean. ;-)
CH
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RE: Crotalus Horridus?
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by earthguy on October 16, 2007
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Daniel (and other DNA doubters), ;)
?????!!!! Phenotypes are the result of controlled expression of genotypes. Ergo we look like our DNA. If DNA says one species, then one species it is. I wouldn't lean on Linneaus as my scientific stalwort, as he thought that he was Adam (as in Adam and Eve) reincarnated. He did a fine job with what he knew, and he set a solid framework for taxonomists to follow. However, he wasn't always right. If you want some real examples of DNA expressing multiple phenotypes (called polymorphism) look at the salamanders. They get really freaky.
Long story short - two morphs, one species (at least at this point in their evolutionary history)
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RE: Crotalus Horridus?
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by Atrox788 on October 16, 2007
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People always like to mention the physical differences between the 2 forms but that hardly warrants a ssp split in modern science. Just because one form may be lighter in color with larger or smaller chevrons do sent mean its a separate form. That logic would have humans broken up in to a multitude of different species or sub species and we all know that is inacurate. Are Canes and Timbers evolving to be separate species? Perhaps. Are they there yet? Definitely not.
Saying that DNA would have us as the same species as primates is just silly. We are very close but obviously different enough to be considered separate even if only by a very small percentage. I wont pretend that I know how to do or read any of this but I trust the people who do it for a living.
The only viable debate on this topic is weather or not a broad enough study sample was used. Aside from that its impossible to logically deny the results.
BTW, Canes are not the Souther population. They are a coastal population. Canes range into VA and you can find true blue mountain horridus south and west of here. Timbers=higher elevations. Canes=Coastal.
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RE: Crotalus Horridus?
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by Chance on October 16, 2007
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Ah, my mistake. I thought my local Arkansas timbers were often referred to as canebrakes as well. In fact, I was assuming all the horridus with the pronounced vertebral stripe and a base color other than black or yellow were usually called canebrakes. Thanks for the clarification.
-Chance
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RE: Crotalus Horridus?
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by Atrox788 on October 16, 2007
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There is some confusion about horridus in your state and what to call the phase. Canebrake is reference to the coastal populations here in the midatlantic and down to the southeast, west too LA. I have heard Arkansas and Oklahoma populations referd to as Canebrakes but having seen the habitat in atleast OK it is definately more along the line of what I would consider Timber habitat. (i.e rocky out cropings. There are virtually no outcroppings in the coastal areas)
Also keep in mind that when I say coastal I am reffering to the coastal plain which can go quite far inland from the coast. I guess swampy or low lying is the best description which usually means coastal at least on this side of the Appalachians.
Also, the east coast populations are the one subject to the most debate. There is no apparent intergrade between coastal populations and mountain populations. There is a distinct line with no obvious sign of horridus all the way down to southern GA. You find them near the coast, in swampy terrain and then have to go hundreds of miles inland to the mountains before you see them again. This segregation is what leads folks to say they are different snakes.
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RE: Crotalus Horridus?
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by Atrox788 on October 16, 2007
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Oh and referring to coloration and markings. I have seen pics of Timbers in the Ozarks which looked like text book Canebrakes. I have also seen first hand Canebrakes in NC which look darker, much like Timbers (one DOR specimen I found earlier this year really looked Timber but I was all of 30 miles from the Outerbanks which is obvious canebrake territory)
Basically coloration and patterns are not definitive taxonomy anymore and for good reason lol
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