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Vivid Reptiles

River Road Alterna - Signature Features

The following set of features associated with River Road alterna is presented here as a guide only. Alterna are by nature notoriously variable animals, varying so much in fact that attempting to create a definitive guide would be a fool's errand. That said, there are physical attributes within the population that are repeated at a fairly high frequency and these more or less common features are presented here.

Signature feature 1
Head shape. It's been argued for years that River Road alterna have rounder, less flattened heads than the more triangular, wider head shapes found in the eastern populations. Though thoroughly anecdotal, I would have to agree  to the head differences having examined hundreds of these animals.
Signature feature 2
Speckled pattern. Although other localities do produce animals with speckling on occasion, this feature turns up with the highest frequency in the River Road population with Black Gaps coming in a very close second. Black Gap speckling differs in that the speckling is usually surrounded, and even interfered with, the white pigment "halo" effect—see Black Gap Signature Features for more on this phenomena.
Signature feature 3
Triple alternates. Again, other populations can and do exhibit this feature but the River Road animals set the standard with gene flow again appearing to be outward.
Signature feature 4
Diamond shaped primaries. Beautiful, symmetrical diamond shaped primaries are quite common here and, some would argue, diagnostic. They seem to occur with about the same frequency as the bat wing (also called bow tie, hourglasse, butterfly, etc.) primaries occur in the Black Gap population and are perhaps analogous. Alterna collected near Lajitas are notable for diamond shaped primaries but this is probably the result of a collecting bias caused by so few animals having ever been collected near Lajitas.
Signature feature 5
Creamy orange. This is a "splitting of the fine hairs" for many, but in most discussions amongst hardcore alterna fans regarding the quality of the primary orange in different alterna localities it regularly comes up that River Road alterna have a different quality of orange. Though the tone of the orange can certainly range, the locality is most notable for a soft, almost pastel orange that is quite unique and beautiful. Somewhat less common River Road examples have a unique "orange" that is more of a tomato red, reminiscent of L. pryomelana base/background color.
Signature feature 6
Mineral gray. River Road gray can range from ultra light platinum to very nearly black with variations of the gray being very common, even amongst littermates. There is a shade of gray that is common and fairly unique to this area that we have anecdotally termed, "mineral gray." This gray is very much like the color of the gray mudstone and volcanic ash found throughout the Big Bend area. A similarly toned, but slightly different gray, occurs frequently in alterna from the Davis Mountains. I have noted over the years that River Road alterna with this mineral gray tend to also develop orange infusion in the gray once they reach adulthood. The orange infusion tends to intensify as the animals age. Some older individuals can appear almost entirely orange or orange-brown. In the early collecting days on the River Road we referred to such brownish and orange toned animals as "buckskins."
Signature feature 7
Extreme pin banding and/or high band count. The River Road population can produce a pattern variant with very narrow primaries and alternates. These narrow pattern variants usually have very high band/alternate counts as well. Some examples seem to have a "blizzard" of bands with banding so dense that the differences between primaries and alternates becomes obscured. This pattern seems to be unique to the River Road. Not to be confused with high speckling.
Signature feature 8
Smaller average size. This is another debatable feature based solely on anecdotal observations. In general, River Road alterna seem to not quite reach the adult sizes obtained by their more eastern brethren. This seems to be especially apparent with wild collected snakes. Though certainly not dainty snakes by any means, the River Roads don't seem to reach the bruiser proportions of alterna encountered from eastern areas such as the Devil's River drainage. Some have proposed that diet (more rodents in the eastern forms) and general sparsity of prey play a roll in this size discrepancy. My own observations indicate that the size differences can be seen under captive conditions as well.