Signature feature 1 |
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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. |
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Signature feature 2 |
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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. |
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Signature feature 3 |
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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. |
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Signature feature 4 |
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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. |
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Signature feature 5 |
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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. |
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Signature feature 6 |
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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." |
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Signature feature 7 |
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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. |
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Signature feature 8 |
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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. |