Reptile & Amphibian Forums

I'm stumped...

I can't figure out if this thing is a trans-pecos or a broad-banded copperhead. I don't have the local info. I've tried reading up on the differences but I can't figure it out without having something to compare it to.

If anyone can help me out I would greatly appreciate it. I'm about to go crazy trying to figure it out.

Thanks alot,
Nick

Would haft to say Trans-Pecos ( A. C. Pictigaster) from the belly pattern and the light spot at the base of each crossband.

Definitely pictigaster, the belly and inverted U's are a dead give-away, Alex

Awesome!!!

Thanks alot guys. I was hoping thats what it would be.

Later,
Nick

Nick,

Although I personally feel that pictigaster is a very poorly-defined race (it was originally thought to be isolated in the mountains of west Texas), here are the currently recognized characteristics (from Dixon [2000]).

pictigaster - "Venter usually heavily mottled with dark color; subcaudals in males usually 57 or more, females usually 52 or more."

laticinctus - "Venter usually uniform tan or orangish pink, with or without a few dark markings; subcaudals in males usually 54 or fewer, females usually 52 or fewer."

The variation in subcaudals between the two forms is actually clinal: higher in the west to lower in the east. Apparently because of that, Roger Conant later on did not stress the use of subcaudal counts as a diagnosing feature between them.

He preferred instead to rely upon the dark ventral coloration (highly variable) and the supposed presence of a light-colored inverted "U" at the base of the dark crossbands to diagnose pictigaster. Unfortunately, this characteristic occasionally turns up in laticinctus from the southern portion of their range.

So, in summary, if you do not know the locality of your specimen, the subcaudal counts are probably the best character in attempting to separate these two subspecies.

Tom Lott

Hi Tom, if I remember correctly, there tends to be a lot of overlap concerning scale counts of any type between these two species. The Gloyd and Conant monograph illustrates this (I don't have it in front of me, so I don't remember exactly how it reads).

I have counted scales from shed skins of my animals and found that subcaudals are somewhat useless (hence the overlap). The belly color has always been the best indicator of species in my experience, and the inverted U's are useful, yet secondary to the belly. I imagine these U's do show up in laticinctus given that gene flow has been documented between these sympatic groups.

Your points are quite valid though. Alex