Agkistrodon contortrix pictigaster

:''Common names: Trans-Pecos copperhead, western copperhead''

''Agkistrodon contortrix pictigaster'' was formerly a venomous pit viper subspecies found in the Trans-Pecos region of the United States in western Texas, and northeastern Mexico. However, recent taxonomic changes do not recognize the Trans-Pecos copperhead (''A. c. pictigaster'') as a valid taxon.

New Taxonomy

The Trans-Pecos copperhead (''Agkistrodon contortrix pictigaster'') Conant R. 1975. ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America''. Second Edition. First published in 1958. Houghton Mifflin Company Boston. 429 pp. 48 plates. (hc), (pb). was once classified as a subspecies of the copperhead (''Agkistrodon contortrix''). However, DNA based studies published in 2008 and 2015, revealed no significant genetic difference between the Trans-Pecos copperhead (''Agkistrodon contortrix pictigaster'') and the broad-banded copperhead, (''Agkistrodon contortrix laticinctus''). The two subspecies were synonymized and elevated to full species, with the oldest published name, ''Agkistrodon laticinctus'', having priority. The resulting taxonomy does not recognize the Trans-Pecos copperhead (''Agkistrodon contortrix pictigaster'') as a valid taxon.Guiher TJ, Burbrink FT (2008). ''Demographic and phylogeographic histories of two venomous North American snakes of the genus Agkistrodon.'' Molecular Phylogenetics and Evolution, 48: 543–553.Burbrink, Frank T. and Timothy J. Guiher. 2014. ''Considering gene flow when using coalescent methods to delimit lineages of North American pitvipers of the genus Agkistrodon.'
Zoological Journal of the Linnean Society, 173: 505–526
Several subsequent reviews and species accounts have followed and supported the revised taxonomy.Crother, B. I. ( editor). 2017. ''Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding, 8th. edition.'' SSAR Herpetological Circular 43, 1–102 pp. (page 59) Powell, Robert, Roger Conant, and Joseph T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, 4th ed. Houghton Mifflin Harcourt Publishing Co. New York. 494 pp. Uetz P, Freed P, Aguilar R, Hošek J (editors) (2021). The Reptile Database,
Agkistrodon laticinctus
' (accessed 30 August 2021) Information on this snake can be found in the ''Agkistrodon laticinctus'' article.

Description

This subspecies is typically a light tan in color, with darker brown, wide crossbands. Their actual color varies by locality, varying from a red-brown, to a gray-brown. The species can be difficult to distinguish from the broad-banded copperhead, '' A. c. laticinctus''. The only notable physical difference between the subspecies is that the Trans-Pecos copperhead tends to have an elaborately patterned underside, often being an irregular, white and black pattern whereas the broad-banded tends to be plain white, only have minimal patterning, or have elongated random blotching instead of a distinct pattern. The subspecies intergrade where their ranges overlap, further confusing identification. It is easily distinguished from other subspecies of copperhead, in that other species typically have banding that narrows at the spine, creating hourglass shapes, whereas ''A. c. pictigaster'' has bands that do not narrow at the spine. They grow to approximately 20-36 inches (50–90 cm) in length. As juveniles, all species of ''Agkistrodon'' have a bright green-yellow color to their tail tip believed to be used as a lure to attract prey items to approach within striking range. The color fades to a grey or brown at about a year of age.

Behavior

Like all ''A. contortrix'' subspecies, ''A. c. pictigaster'' is a nocturnal ambush predator. Their diet consists of primarily lizards, frogs, and rodents. Their choice of habitat is the driest among the copperhead subspecies, preferring rocky, lightly vegetated, canyon areas. They are ovoviviparous, giving birth to a litter of up to 8 young in the early fall.

Venom

Like most pit viper species, ''A. contortrix'' has a hemotoxic venom, which is delivered through hinged, hollow fangs set in the front of their jaw. The fangs work like hypodermic needles, injecting the venom in a single, quick striking motion. Copperhead venom is not considered to be life-threatening to an otherwise healthy adult, but it can cause localized swelling, necrosis, and severe pain. Any bite from a venomous snake should be considered serious and medical treatment sought. There is no antivenin specifically manufactured for copperheads, but CroFab, which makes use of the venom from the cottonmouth ('' Agkistrodon piscivorus''), can be used in cases of a severe envenomation.

References

External links

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''Agkistrodon contortrix''
a
University of Texas
Accessed 7 December 2007.


a
WhoZoo
Accessed 7 December 2007.

{{Taxonbar, from=Q11684612

contortrix pictigaster
Reptiles of the United States