Micruroides euryxanthus, commonly known as the Sonoran coral snake or the Arizona coral snake, is a species of venomous elapid, which is endemic to northwestern Mexico and the Southwestern United States.
Adults are 11â"24 inches (280â"610Â mm) in total length (including tail).
The color pattern consists of broad, alternating rings of red and black, separated by narrower rings of white or yellow. Markings become paler as they reach the belly. The head is black, the black extending to the posterior border of the parietals.
Micruroides euryxanthus resembles Micrurus fulvius. However, the white or yellow rings are broader than in Micrurus fulvius, and there are fewer black rings on the tail, usually only 2. Also, the first ring on the body (the first ring behind the white or yellow ring on the back of the head) is red, whereas in Micrurus fulvius it is black.
The venom is neurotoxic and extremely potent, but no fatalities have been reported.
M. euryxanthus is found in arid/semiarid regions in numerous habitats, both on plains and on lower mountain slopes, from sea level to 5,800Â ft (1,800Â m). In Arizona it is abundant in rocky upland desert.
The Sonoran coral snake usually stays underground and comes out at night, but can also appear during and after rains.
When startled or threatened, M. euryxanthus will hide its head under its body and raise and tightly curl its tail. While in this posture, it will sometimes forcibly and noisily emit gas from its cloaca, a behavior known as "cloacal popping".
The Arizona coral snake preys upon small snakes, predominantly Leptotyphlops, but also Chionactis, Hypsiglena, Sonora, and Tantilla. It will also eat small lizards such as skinks.
Like all other species of New World coral snakes (genera Leptomicrurus and Micrurus), Micruroides euryxanthus is oviparous. Adult females may lay up to 3 eggs, and the hatchlings are 18-20 cm (7-8 inches) in total length.
Micruroides euryxanthus is found from central Arizona and southwestern New Mexico to MazatlÃ¡n in southern Sinaloa. Isolated populations are also found in the Chocolate Mountains, La Paz County, western Arizona and on TiburÃ³n Island in the Gulf of California.
Three subspecies are recognized, including the nominotypical subspecies.
- Micruroides euryxanthus australis Zweifel & Norris, 1955
- Micruroides euryxanthus euryxanthus (Kennicott, 1860)
- Micruroides euryxanthus neglectus Roze, 1967
- Kennicott, R. 1860. Descriptions of New Species of North American Serpents in the Museum of the Smithsonian Institution, Washington. Proc. Acad. Nat. Sci. Philadelphia 12: 328-338. (Elaps euryxanthus, pp. 337-338.)
- Roze, J.A. 1974. Micruroides, M. euryxanthus. Catalogue of American Amphibians and Reptiles (163): 1-4. (Micruroides euryxanthus neglectus)
- Wright, A.H., and A.A. Wright. 1957. Handbook of Snakes of the United States and Canada. Comstock. Ithaca and London. 1,105 pp. (in 2 volumes) (Family Elapidae, p. 885; Genus Micruroides, pp. 885-886; and Micruroides euryxanthus, pp. 886-890, Figures 253.-255. + Map 63. on p. 891.)
- Zweifel, R.G., and K.S. Norris. 1955. Contributions to the herpetology of Sonora, Mexico: Descriptions of new subspecies of snakes (Micruroides euryxanthus and Lampropeltis getulus) and miscellaneous collecting notes. Amer. Midland Naturalist 54: 230-249. (Micruroides euryxanthus australis, p. 238.)