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RE: Validity of C. horridus atricaudatus
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by fizzbob7 on August 7, 2005
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for instance:
http://www.venomousreptiles.org/libraries/showfilepage/2408?offset=54
and mine from south georgia:
http://www.venomousreptiles.org/libraries/showfilepage/1890?offset=50
they look similar enough to me, yet are from completely different places.......either the first one is mislabeled or mine is an oddball (i had 2 exactly like him though from the same exact county in south GA, so it couldn't be that odd)
it seems to me that the further north you go, the darker they'd be so they could heat up quicker in the cooler weather....but south GA isn't exactly cold from spring to fall......and i've seen a few dark ones there, and a few yellow ones, and few grayish pink ones......
it's all a guessing game
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RE: Validity of C. horridus atricaudatus
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by Cro on August 9, 2005
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Ricky: The two links to photos that you say look similar to you are not similar to me at all. The differene is huge. It is like comparing a poodle to a pit bull, they are nothing alike except being both dogs. Like Chris stated above, there are many people who see a huge difference between these snakes from different areas of the country, it just takes more field experience. Also, you seem to be missing some of the more subtile details and mostly looking at coloration. You have to look at a the pattern, and the shape of the pattern elements, the coloration, the head shape, the body mass, a whole combination of things at once, and that is something that is very difficult to explain to someone how to do. JohnZ
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RE: Validity of C. horridus atricaudatus
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by SwampY on August 9, 2005
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C horridus horridus is yellow to gray or black in ground color, lacks a distinct middorsal stripe and has 23 (21-26) midbody scale rows and 15-34 dorsal body bands. This subspecies inhabits upland wooded areas with nearby wooded ledges. Females of this species sexually mature at 77cm. This subspecies brumates in communal spaces. This subspecies has a rounded club shaped head. This subspecies has a weaker venom with low neurotoxic levels.
C horridus atricaudatus is pinkish brown or gray in ground color, has a distinct reddish orange mid-dorsal stripe, 25 (21-25) midbody scale rows, and 21-29 dorsal body bands. This subspecies inhabits lowland swampy areas and pine thickets. Females from this subspecies bear their initial litter at an svl of more than 100 cm. This subspecies does not den, and brumates singly or in small numbers. This subspecies has a more "arrowhead" shaped head, flat with sharper angles. This subspecies has a much stronger venom with higher neurotoxic levels.
Keep in mind that Brown & Ernst's study only separated populations east of the appalachian mountains into the two subspecies and Pisani's study only took into account populations from the west where areas of intergradation occur.
Most of this information came from Venomous Reptiles of North America by Carl Ernst. Hope this is what you want Fizzbob
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RE: Validity of C. horridus atricaudatus
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by AquaHerp on August 10, 2005
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Technically, horridus (or a sub if you want to argue that one) can't be pinned to "giving birth at..." a predetermined size. It's more of an age factor determining this than a size thing. Although one could argue in the wild that a snake shouldn't reach a certain size until its "such and such" year. But that's irrelevant.
My theory is they will indeed split them again. I also trust that by the time the academia world and their taxonomists with their new mitochondrial DNA are done trying to make names for themselves that every single individual animal out there will be its own subspecies.
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RE: Validity of C. horridus atricaudatus
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by Chris_Harper on August 10, 2005
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I think the second portion of Chad's postulation is the most controversial. Ginger Clark's studies showed northern and southern horridus to be genetically indistinguishable under the microscope so to speak. I don't even know what the standard is, or where they "draw the line". All scientists definitely do not "dance to the same music".
I quote a CNN article: "Ginger Clark, a senior biological scientist at the University of Florida, developed a technique that can not only determine the species of an organism based on tissue samples or blood but also the gender of the organism."
That's pretty specific, and she's probably forgotten more about DNA than I'll ever know, so I'll leave that up to the other taxonomists to sort out.
~CH
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RE: Validity of C. horridus atricaudatus
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by SwampY on August 10, 2005
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Chris,
She doesn't say that they are genetically indistinguishable., Quite the contrary -- She even goes so far as to call them "population segments", "morphotypes", and explains that the proposed "groupings" of western, northern, and southern would be in line with genetic differences she observed.
In my opinion, after reading the article and talking with Ginger during and after the study, she chickened out.
She threw the (genetic) feathers on the table, she threw the (genetic) bill on the table, she threw the (genetic) webbed flat feet on the table, she played the (genetic) recordings of "quack quack quack" then just when you're getting to the part in the paper when you expect her to declare "It's a Duck!" .. she twiddles her toes in the sand and murmurs in a squeaky and cracking little voice "uuhmmmm ... it's not a duck"
Here is an abstract of the paper
http://www.bioone.org/bioone/?request=get-document&issn=0022-1511&volume=037&issue=01&page=0145
Even without Ginger's paper, "If it walks like a ....
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RE: Validity of C. horridus atricaudatus
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by SwampY on August 10, 2005
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http://www.biotech.ufl.edu/GeneticAnalysis/Projects.html
"Ginger Clark, lab coordinator, is looking at the phylogeography and fine scale population structure of Crotalus horridus, the timber/canebrake rattlesnake, using mtDNA and microsatellite surveys. This species has never undergone any extensive genetic examination so this is ground breaking research. Venom analysis on the canebreak rattlesnakes is also in the works."
hmmmmmmmmmmmmmmmmmmmm
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My experience has been.....
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by MattHarris on August 16, 2005
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..that the snakes are easily identifiable in terms of 'highland/mountain' phases and 'lowland' phases. In that I mean, if you find a timber from NC Pennsylvania(Black or yellow) or Upstate NY....they are obviously not canebrakes. Could I tell them from a montane snake from North Georgia or KY??? Hmmm, maybe not, but there'd be no mistaking a coastal canebrake from SC, NC, GA, or FL.
I tend to agree with Doug(AquaHerp)...when the taxonomists get done splitting hairs, everything will be a new species or subspecies... I only wish more time would be spent trying to explane the prehistoric evolution of pitvipers and figure out why bushmasters are so different. I'm not buying the Bering land bridge theory....I think they came over from Africa via S.America.
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RE: My experience has been.....
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by Chris_Harper on August 17, 2005
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Manny Rubio told me 4 years ago that he thought that 4 subspecies of horridus should be recognized. It's not my field of expertise, so I'll be on the sidelines while the lumpers and splitters duke it out.
~CH
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RE: Validity of C. horridus atricaudatus
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by H20mocasin on August 19, 2005
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Here is my take on this. everywhere in the southeast...Alabama, mississippi, georgia, south carolina, and SE North Carolina there are canebrakes and eastern diamondbacks in overlapping state parks...but not same habitats....the same thing is true of stokes county, nc. west of pilot mountain you'll find timbers...south and east you'll find canebrakes...until you reach greensborough there is really no habitat evidence of a subspecies because crotalus horridus occurs in this rugged terrain. Now if you go to the Enos River region..they claim to have timbers...but i think they are canes. Getting back to my theory that there might be a third subspecies of crotalus horridus in the lowcountry of SC and GA. This region favors both prelevant habitat for diamondbacks and canes...yet you'll rarely find them together. However when i was in jasper county many locals talked of a diamond-canebrake snake that was frequently reported in neighbors' backyards around the Savanna river banks. I am wondering due to a lack of pure canes in this region...diamondbacks are more common...but around edisto this isn't the case as canebrakes are more common. Im just hypothesizing can you imagine if there was a third subspecies. just as Tuscon Arizon has two subspecies of twin spotted rattlesnakes in the west and east saugaro national parks...could there be any doubt of a new gene pool of left over male canes trying desperatley to find a mate and get confused when dening up with an accidental female eastern diamondback. many textbooks and field guides show this pattern as a morph...but the possibilites are great down in this rural sc county.
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