Reptile & Amphibian Forums

What's a good source for the latest documented range of alterna? I'm primarily interested in the northern end of the range--Iraan is the furthest north I can think of. Is the Pecos River considered the northern edge of the range?
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Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet

Chris: Do you have a copy of Werler & Dixon ("Texas Snakes"? If not, I can email you a pdf of their distribution map. Otherwise, I'm not aware of anything of more recent vintage that has been published.

cheers,

Bob Hansen
rwh13@csufresno.edu

>>Chris: Do you have a copy of Werler & Dixon ("Texas Snakes"?

I see in your original post you fell victim to the "unintentional smiley" that happens when you put quotation marks followed by a parenthesis.

I don't have that book, but I've looked through it at Borders "This Isn't a Library" Book Store. If I'm recalling correctly, the range maps in the book have those little dots representing official records, such as dead snakes pickled and packed away in universities. I don't think they would list all occurrences of alterna, because they don't generally include hobbyist records--I know of another species of snake which exists further west than the book documented. Nevertheless, I'd still like to get the book soon, but I'm currently on a wife-imposed moratorium on book purchases!

I'm hoping to hear from some folks on here about the "well, the book says this, but I know they're found X miles further N/S/E/W than that" kind of stuff. Personally, I've yet to find one, even though it hasn't been for lack of trying! However, my searches have all been in Val Verde County, and I was hoping to get some leads on stuff a little further north.

If not, I can email you a pdf of their distribution map.

I'd be interested in seeing it--does the book mention any barriers to dispersion (e.g. Pecos River)?
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Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet

The area diretly north of Iraan is the King Mountain / Castle Mountain "mesas". These lie in Upton county and numerous alterna have been collected there (mostly dark blairs... I know of 2 "alterna" morphs...)
The Pecos River is no wider than 25 feet across and 8 feet deep at its widest and deepest in that area, so it is really not a barrier at all.
The real question is why don't E. bairdi and C. lepidus range up to King Mtn.? Alterna do, bogeys do, blacktails do, but not these guys.

Happy herpin'...

MP

>>The area diretly north of Iraan is the King Mountain / Castle Mountain "mesas". These lie in Upton county and numerous alterna have been collected there (mostly dark blairs... I know of 2 "alterna" morphs...)

I might have to check that area then.

>>The Pecos River is no wider than 25 feet across and 8 feet deep at its widest and deepest in that area, so it is really not a barrier at all.

It may not seem like much, but there are "wimpier" rivers which are pretty effective barriers (Red River on OK-TX border west of Lake Texoma, for example) for some species, but not for others.

>>The real question is why don't E. bairdi and C. lepidus range up to King Mtn.? Alterna do, bogeys do, blacktails do, but not these guys.

I think I've heard rumors of bairdi ranging eastward into the Camp Bullis area of San Antonio (I don't have maps in front of me, but I think they're found elsewhere on the Edwards Plateau). molossus is found in Bexar County for sure (per TPWD recent surveys). I was hoping to check out both locations this past year, but had to move before I got the chance!
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Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet