East Texas and West Texas, Terlingua Report

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reptileexperts
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East Texas and West Texas, Terlingua Report

Post by reptileexperts » October 12th, 2013, 3:06 pm

Just returned from a week of herping in Terlingua, Texas, after a few days in East Texas herping. With the closure of the national park, hiking during the day was cut a bit, but we managed to do some hiking in Closed Canyon, within the Big Bend Ranch State Park. Most herping was done at night, but with the first night and the last night the only nights showing us favorable temperatures, we were let down in the herp department, despite hours of driving around and walking cutouts and flipping rocks.

Snake wise we had far greater success in East Texas herping my normal spots -
6 - Thamnophis proximus orarius
8 - Agkistrodon piscivorus leucostoma
2 - Storeria dekayi limnetes
1 - Nerodia erythrogaster juvenile
1 - DOR Nerodia clarkii clarkii
1 - Agkistrodon contortrix contortrix

In West Texas, during the day the most common species found was the Crevice Spiny Lizard, Sceloporus poinsettii with a few Spotted Whiptails, Aspidoscelis scalaris septemvittata showing up as well. No banded geckos were found during flipping, and with our efforts hiking during the warmer part of the days (getting to 81 at the hottest of most of the days) we turned up no horned lizards as well.

The first day though, gave way to a very large and cooperative Sonoran Gopher Snake (lifer) Pituophis catenifer affinis basking during the setting of the sun. The only other species of snakes documented were (2) Masticophis flagellum testaceus screaming across the road during a drive into Alpine for supplies, and on our final night of walking and driving back from OJ Mexico, we finally started getting rattlesnakes after the days temperatures reached 92 in the region with our first finding of a Crotalus scutulatus (lifer!) basking on the shoulder, followed 5 minutes later by my lifer Crotalus molossus basking in the middle of the road. We pulled over to get out and photograph it as it set and wait for it to move to a cut, but before we could even get out of the car with our gear, a moving truck flew down the highway and ran over its head with both tires, directly in front of our eyes. . . still have nightmares of such events :( All in all, it was a good getaway, and a nice time for my girlfriend from Germany who wanted some hands on time with some of the Agkistrodon and Crots from the Americas. Here are a few shots of our findings - Enjoy

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Agkistrodon contotrix contortrix

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Agkistrodon piscivorus leucostoma

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Storeria dekayi limnetes

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Crotalus molossus molussus still biting and rattleing while we moved him from the road after being hit

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Pituophis catenifer affinis we still had some debate as to whether this may be a Texas Bull, but the tail pattern and clean head sure fit for P catenifer

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Crotalus scutulatus in situ

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in field studio

You can see all my images over at http://www.pbase.com/codyconway, feel free to ask any clarifying questions about style, equipment used, and so forth. But no exacts - per policy - on where snakes were located.

Cheers,

Cody Conway

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Brian Hubbs
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Re: East Texas and West Texas, Terlingua Report

Post by Brian Hubbs » October 12th, 2013, 5:48 pm

That is a Sonoran gopher...the whole Bend region has those, not Bulls.

reptileexperts
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Re: East Texas and West Texas, Terlingua Report

Post by reptileexperts » October 13th, 2013, 2:55 pm

Thanks Brian, I had not checked specific locale range on both species, according to the transpecos region maps, both occur within big bend, but we were nearly certain on the ID being Sonoran, thanks for clearing that up.

WW**
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Re: East Texas and West Texas, Terlingua Report

Post by WW** » October 14th, 2013, 4:37 am

Nice photos.

One ID correction: sorry to spoil a lifer, but the "Crotalus scutulatus" is a Crotalus atrox - note "salt and pepper" markings, small scales on snout, light line from behind eye meeting edge of mouth, ill-defined light edges of diamond markings. The commonly used criterion of relative width of dark and light tail bands is often misleading.

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azatrox
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Re: East Texas and West Texas, Terlingua Report

Post by azatrox » October 14th, 2013, 5:58 am

Nice series.

Your Crotalus molossus molossus is actually a Crotalus ornatus. Generally anything east of the Continental Divide is ornatus and anything west is molossus.

-Kris

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chris_mcmartin
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Re: East Texas and West Texas, Terlingua Report

Post by chris_mcmartin » October 14th, 2013, 4:27 pm

azatrox wrote:Nice series.

Your Crotalus molossus molossus is actually a Crotalus ornatus. Generally anything east of the Continental Divide is ornatus and anything west is molossus.
Am I the only person not yet on board with this change? :lol:

reptileexperts
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Re: East Texas and West Texas, Terlingua Report

Post by reptileexperts » October 14th, 2013, 4:31 pm

In ALL my field text, it's still referred to as the Northern Black-tailed Rattlesnake, C molossus :|

I did confirm via scale counts on the head that the other Crotalus was not Mojave, but the scale count also does not agree with Atrox? Is there some variation to the atrox count that Im not aware of? This particular Crotalus was highly aggressive, very much more than any atrox I've ever worked with (many that it is). It would throw its' entire body into a strike, and literally jump when it did. It never ceased to rattle, and would never let its guard down - again all different to atrox I've worked with in central, south, and south east Texas. I'll post a head shot for the scales tomorrow but the count is 4 rows of scales between the two ocular scales. Mojave count = 2, atrox count = 3.

Cheers

reptileexperts
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Re: East Texas and West Texas, Terlingua Report

Post by reptileexperts » October 14th, 2013, 4:32 pm

Image
Another shot of the Agkistrodon contortrix contortrix :thumb:

WW**
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Re: East Texas and West Texas, Terlingua Report

Post by WW** » October 14th, 2013, 10:27 pm

reptileexperts wrote:In ALL my field text, it's still referred to as the Northern Black-tailed Rattlesnake, C molossus :|
The paper highlighting the distinction only came out last year, so unless you only bought the guides since then, it's a bit much to expect clairvoyance of them ;)
I did confirm via scale counts on the head that the other Crotalus was not Mojave, but the scale count also does not agree with Atrox? Is there some variation to the atrox count that Im not aware of? This particular Crotalus was highly aggressive, very much more than any atrox I've ever worked with (many that it is). It would throw its' entire body into a strike, and literally jump when it did. It never ceased to rattle, and would never let its guard down - again all different to atrox I've worked with in central, south, and south east Texas. I'll post a head shot for the scales tomorrow but the count is 4 rows of scales between the two ocular scales. Mojave count = 2, atrox count = 3.
All species vary in temper - a lot of Mohaves are psychopathic headbangers, but I have also seen dog-tame ones that could not even be persuaded to donate venom for the cause when pinned and milked in the usual manner. The reverse can work as well.

Look forward to the head shot. You mean 3 scales between the supraoculars (the large scales over the eyes), right? They are variable, as anything in biology, but the fact that yours had more scales rather than fewer says atrox more than Mohave. C. atrox often has more than 3. Then again, some Mohave have more than 2. Everything else about that snake definitely says atrox.

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azatrox
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Re: East Texas and West Texas, Terlingua Report

Post by azatrox » October 15th, 2013, 10:52 am

Am I the only person not yet on board with this change?

Yes Chris you are the only one. Get with the program buddy. All the cool kids are. ;)

Re the head scalation, C. s. scutulatus will have relatively few (2-3) larger scales between the supraoculars. C. atrox will have more (usually 4-6) smaller scales between the supraoculars.

The animal pictured is 100% atrox. Head shape, body shape, etc. all point to atrox. Other than passing similarity (i.e. diamond pattern,ringed tail, etc.) nothing about that animal says scutulatus.

-Kris

Aaron
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Re: East Texas and West Texas, Terlingua Report

Post by Aaron » October 15th, 2013, 6:13 pm

I believe there are several places in west TX where atrox and scutes hybridize. That said, it looks atrox to me but I'm no expert.

troy hibbitts
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Re: East Texas and West Texas, Terlingua Report

Post by troy hibbitts » November 19th, 2013, 11:48 am

haha . . . no, Chris, you're not the only one not buying the C.ornatus vs C.molossus split . . . and I've read the publication. It just another one of these mitochondrial DNA-based splits (which can't assess gene flow between pops) and does not reflect the phenotypic appearence of western NM snakes all that well, as the two forms seem to intergrade west of the Rio Grande into the Gila Mts.

Pituophis throughout most of the eastern Trans Pecos (from Alpine east to Sanderson) are more or less intergrades between sayi and affinis.

Troy

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