Micruroides

Micruroides is a genus of venomous coral snake in the family Elapidae. The genus is monotypic, containing only the species Micruroides euryxanthus.

Micruroides euryxanthus
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Elapidae
Genus:	Micruroides K.P. Schmidt, 1928[2]
Species:	M. euryxanthus
Binomial name
Micruroides euryxanthus (Kennicott, 1860)
Synonyms
Elaps euryxanthus Kennicott, 1860 Micrurus euryxanthus — Stejneger & Barbour, 1917[3] Micruroides euryxanthus — K.P. Schmidt, 1928[2]

Sonoran coral snake in Arizona.

Micruroides euryxanthus, commonly known as the Sonoran coral snake or the Arizona coral snake, is endemic to northwestern Mexico and the southwestern United States.

Description

Adults of M. euryxanthus are 11-24 inches (28–61 cm) long. [4]

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,[4] the black extending to the posterior border of the parietals.[5]

The smooth dorsal scales are arranged in 15 rows at midbody. The ventrals number 214-241. The anal plate is divided. The subcaudals number 21-34, and are divided (paired).[6]

Micruroides euryxanthus resembles Micrurus fulvius. However, the white or yellow rings are broader than in M. fulvius, and there are fewer black rings on the tail, usually only 2.[6] 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.[7]

Venom

The venom of M. euryxanthus is neurotoxic and extremely potent, but no fatalities have been reported.[4]

Habitat

M. euryxanthus is found in arid and semiarid regions in numerous habitats, both on plains and on lower mountain slopes, from sea level to 5,800 ft (1,800 m). In Arizona it is abundant in rocky upland desert.

Behavior

The Sonoran coral snake usually stays underground and comes out at night, but can also appear during and after rains.

Defense

When startled, frightened, or threatened, M. euryxanthus will hide its head under its body and raise and tightly curl its tail. While in this posture, it will "fart": snakes do not have an anal cavity in the sense that humans and most mammals do, but rather a tract that allows for both disposal of waste and for laying of eggs in females. Instead, it will forcibly and noisily emit gas from its cloaca, a behavior known as "cloacal popping", and predictably this phenomenon has a very unpleasant smell.[6][8]

Diet

The Arizona coral snake preys upon small snakes, predominantly Leptotyphlops, but also Sonora, and Tantilla.[9] It will also eat small lizards such as skinks.[10]

Reproduction

Like all other species of New World coral snakes (genera Leptomicrurus and Micrurus), Micruroides euryxanthus is oviparous.[6] Adult females may lay up to 3 eggs, and each hatchlings is 18–20 cm (7-8 inches) in total length.[9]

Geographic range

USA Coral Snake Range

Micruroides euryxanthus is found from central Arizona and southwestern New Mexico to Mazatlán in southern Sinaloa. Isolated populations are also found in the Chocolate Mountains, La Paz County, western Arizona and on Tiburón Island in the Gulf of California.[10]

Subspecies

Three subspecies are recognized, including the nominotypical subspecies.[11]

• Micruroides euryxanthus australis Zweifel & Norris, 1955
• Micruroides euryxanthus euryxanthus (Kennicott, 1860)
• Micruroides euryxanthus neglectus Roze, 1967

Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Micruroides.

References

1. Frost DR, Hammerson GA, Gadsden H (2007). "Micruroides euryxanthus ". IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org. Downloaded on 10 January 2013.
2. Schmidt KP (1928). "Notes on American Coral Snakes". Bull. Antivenin Inst. America 2 (3): 63-64. (Micruroides, new genus).
3. Stejneger L, Barbour T (1917). A Check List of North American Amphibians and Reptiles. Cambridge, Massachusetts: Harvard University Press. 125 pp. (Micrurus euryxanthus, p. 106).
4. Reptiles and Amphibians of Arizona. www.reptilesofaz.org/Snakes-Subpages/h-m-euryxanthus.html.
5. Boulenger GA (1896). Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the Colubridæ (Opisthoglyphæ and Proteroglyphæ) ... London: Trustees of the British Museum (Natural History). (Taylor and Francis, Printers.) xiv + 727 pp. + Plates I-XXV. (Elaps euryxanthus, p. 415).
6. Smith HM, Brodie ED Jr (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN 0-307-13666-3 (paperback). ("Elapids—family Elapidae" and "Micruroides euryxanthus", pp. 196-197).
7. Schmidt KP, Davis DD (1941). Field Book of Snakes of the United States and Canada. New York: G.P. Putnam's Sons. 365 pp. (Micruroides euryxanthus, pp. 276-277, Figure 91).
8. Ernst CH, Ernst EM (2011). Venomous Reptiles of the United States, Canada, and Northern Mexico. Volume 1: Heloderma, Micruroides, Micrurus, Pelamis, Agkistrodon, Sistrurus. Baltimore: Johns Hopkins University Press. xviii + 392 pp. ISBN 0-8018-9875-7. (Micruroides euryxanthus ... behavior, p. 111).
9. Hubbs B, O'Connor B (2012). A Guide to the Rattlesnakes and other Venomous Serpents of the United States. Tempe, Arizona: Tricolor Books. 129 pp. ISBN 978-0-9754641-3-7 (paperback). (Micruroides euryxanthus euryxanthus, pp. 86-87, 122).
10. Stebbins RC (2003). A Field Guide to Western Reptiles and Amphibians, Third Edition. The Peterson Field Guide Series ®. Boston and New York: Houghton Mifflin. 533 pp. ISBN 0-395-98272-3 (paperback). (Micruroides euryxanthus, pp. 405-496 + Plate 44 + Map 181).
11. "Micruroides euryxanthus ". ITIS (Integrated Taxonomic Information System). www.itis.gov.

Further reading

• Behler JL, King FW (1979). The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp., 657 color plates. ISBN 0-394-50824-6. (Micruroides euryxanthus, pp. 680-681 + Plate 616).
• 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, new species, pp. 337–338).
• Roze JA (1974). "Micruroides, M. euryxanthus ". Catalogue of American Amphibians and Reptiles (163): 1-4. (Micruroides euryxanthus neglectus).
• Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock. 1,105 pp. (in 2 volumes) (Family Elapidae, p. 885; Genus Micruroides, pp. 885–886; Micruroides euryxanthus, pp. 886–890, Figures 253-255 + Map 63 on p. 891).
• Zweifel RG, Norris KS (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, new subspecies, p. 238.)