Agkistrodon contortrix phaeogaster
Agkistrodon contortrix phaeogaster was formerly a venomous pit viper subspecies found in the central region of the United States. However, recent taxonomic changes do not recognize the Osage copperhead as a valid taxon.
New Taxonomy
The Osage copperhead was once classified as a subspecies of the copperhead. However, DNA based studies published in 2008 and 2015, revealed no significant genetic difference between the Osage copperhead, the southern copperhead,, and the northern copperhead. The three subspecies were synonymized and elevated to one species, with the oldest published name, Agkistrodon contortrix, having priority. The resulting taxonomy does not recognize the Osage copperhead as a valid taxon. Several subsequent reviews and species accounts have followed and supported the revised taxonomy. Information on this snake can be found in the Agkistrodon contortrix article.Description
Gloyd and Conant gives maximum total lengths of 990 to 723 mm for males and females, respectively, while mentioning that other sources give a maximum total length for this subspecies of 1,016 mm regardless of sex.The color pattern is similar to that of A. c. mokasen, except that the dark bands are in sharper contrast to the lighter ground color, and with no smaller dark spots between them.
Geographic range
Found in the United States in eastern Kansas, extreme southeastern Nebraska and a large part of Missouri. The type locality given is "10 miles south of McLouth, Jefferson County, Kansas."Venom
The venom of Agkistrodon contortrix phaeogaster is similar to the venoms produced by other species of the Agkistrodon genus. The exact ratio of toxins to each other varies among species and gender, as does the overall potency of the venom. The venom is most potent between the late-spring and mid-summer months, this rise in toxicity commences 2–3 weeks prior to reaching peak toxicity. While the initial reduction of potency occurs over approximately one month, the snake's venom remains slightly more toxic throughout the late-summer months until beginning a slow descent to reach its original toxicity by mid-fall.Danger to humans
The bite of the Osage copperhead is considered a medical emergency and the victim should be brought to a hospital immediately for the best prognosis.The effects of the toxic venom present with a predictable course of symptoms until treatment is received. Immediate and severe pain, oozing of blood from the fang punctures, considerable edema, epistaxis, bleeding of the gums, marked hematuria, general petechiae, shock, renal failure, and local necrosis. These effects are attributed to the various haemotoxins and necrotoxins contained in the venom. Many other toxins are present in the venom in small quantities and are not clinically significant due to their extremely low concentrations.