Hypsiglena torquata

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA DIPSADIDAE

Scientific Name: Hypsiglena torquata
Species Authority: (Gunther, 1860)
Common Name(s):
English Nightsnake, Night Snake
Synonym(s):
Hypsiglena gularis Tanner, 1954
Taxonomic Notes: There have been various arrangements of species within this genus and undoubtedly the current arrangement followed here can be expected to change again in the near future.

The populations on Isla Partida Norte, in the Gulf of California, Mexico are sometimes considered to be a separate species (Grismer 1999, 2000).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Hammerson, G.A., Frost, D.R., Santos-Barrera, G., Vasquez Díaz, J. & Quintero Díaz, G.E.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Least Concern in view of the large and probably relatively stable extent of occurrence, area of occupancy, number of subpopulations, and population size. This species is not threatened in most of its range.

Geographic Range [top]

Range Description:The species' range extends from southern British Columbia, Idaho, Utah, Colorado, and Kansas southward through the southwestern United States to southern Baja California (including Isla Partida Norte, in the Gulf of California) and Guerrero in mainland Mexico, at elevations from near sea level to around 2,650 m asl (8,700 feet) (Stebbins 2003). Reports of occurrences as far south as Costa Rica (e.g., Ernst and Ernst 2003) are incorrect (Savage 2002).
Countries:
Native:
Canada; Mexico; United States
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by hundreds of occurrences or subpopulations. The total adult population size is unknown but undoubtedly exceeds 100,000. The species occupies a wide range and is locally fairly common. The extent of occurrence, area of occupancy, number of subpopulations, and population size are probably relatively stable. The population in Mexico is stable.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This snake generally inhabits arid and semi-arid plains, flats, canyons, and hillsides, usually rocky, dissected or hilly terrain with sandy or gravelly soils, including desert (e.g., creosote bush, sagebrush), prairie, foothill grassland, chaparral, thornscrub, thornforest, pinyon-juniper woodland, scrubby oak-juniper savanna, mesquite savanna, pine-hardwood woodland, and sometimes moist mountain meadows (Degenhardt et al. 1996, Hammerson 1999, Werler and Dixon 2000, Stebbins 2003). Periods of inactivity are spent under rocks or other surface cover, in crevices, or underground. In Idaho, individuals can be found under surface rocks in spring, but not in summer. It feeds on small amphibians and reptiles, and is an oviviparous species.
Systems: Terrestrial

Threats [top]

Major Threat(s): No major threats to this species have been identified. The habitat generally tends to be unsuitable for human settlement.

Conservation Actions [top]

Conservation Actions: Many occurrences of this species are in national parks and other well-protected areas.

Bibliography [top]

Anderson, J.D. and Lidicker Jr., W.L. 1963. A Contribution of our Knowledge of the Herpetofauna of the Mexican State of Aguascalientes. Herpetologica 19(1): 40-51.

Bostic, D.L. 1971. Herpetofauna of the Pacific coast of north central Baja California, Mexico, with a description of a new subspecies of Phyllodactylus xanti. Transactions of the San Diego Society of Natural History 16: 237-264.

Crother, B.I., Boundy, J., Campbell, J.A., de Queiroz, K., Frost, D.R., Highton, R.H., Iverson, J.B., Meylan, P.A., Reeder, T.W., Seidel, M.E., Sites Jr., J.W., Taggart, T.W., Tilley, S.G. and Wake, D.B. 2000. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and Reptiles, Herpetological Circular No. 29. 82 pp.

Crother, B.I., Boundy, J., Campbell, J.A., de Quieroz, K., Frost, D., Green, D.M., Highton, R., Iverson, J.B., McDiarmid, R.W., Meylan, P.A., Reeder, T.W., Seidel, M.E., Sites Jr, J.W., Tilley, S.G. and Wake, D.B. 2003. Scientific and standard English names of amphibians and reptiles of North America north of Mexico: update. Herpetological Review 34: 196-203.

Degenhardt, W.G., Painter, C.W. and Price, A.H. 1996. Amphibians and Reptiles of New Mexico. University of New Mexico Press, Albuquerque, New Mexico. Xix + 431 pp.

Diller, L.V. and Wallace, R.L. 1986. Aspects of the life history of the desert night snake, Hypsiglena torquata deserticola: Colubridae, in southwestern Idaho. Southwestern Naturalist 31: 56-64.

Dixon, J.R. and Dean, R.H. 1986. Status of the southern populations of the night snake (Hypsiglena: Colubridae) exclusive of California and Baja California. Southwestern Naturalist 31: 307-318.

Ernst, C.H. and Ernst, E.M. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.

Grismer, L.L. 1993. The insular herpetofauna of the Pacific coast of Baja California, Mexico. Herpetological Natural History 1: 1-10.

Grismer, L.L. 1999. An evolutionary classification of reptiles on islands in the Gulf of California, México. Herpetologica 55(4): 446-469.

Grismer, L.L. 1999. Checklist of the amphibians and reptiles on islands in the Gulf of California. Bulletin of the Southern California Academy of Sciences 98(2): 45-56.

Grismer, L.L. 2001. An evolutionary classification and checklist of amphibians and reptiles on the Pacific islands of Baja California, Mexico. Bulletin of the Southern California Academy of Sciences 100: 12–23.

Grismer, L.L. 2002. Amphibians and Reptiles of Baja California, Including its Pacific Islands and the Islands in the Sea of Cortés. University of California Press, Berkeley and Los Angeles, California.

Grismer, L.L., McGuire, J.A. and Hollingsworth, B.D. 1994. A report on the herpetofauna of the Vizcaíno peninsula, Baja California, Mexico, with a discussion of its biogeographic and taxonomic implications. Bulletin of the Southern California Academy of Sciences 93: 45-80.

Hammerson, G.A. 1999. Amphibians and reptiles in Colorado. Second edition. University Press of Colorado, Boulder, Colorado.

Hardy, L.M. and McDiarmid, R.W. 1969. The amphibians and reptiles of Sinaloa, México. University of Kansas Publications, Museum of Natural History 18: 39-252.

IUCN. 2007. 2007 IUCN Red List of Threatened Species. Available at: www.iucnredlist.org. (Accessed: 12th September 2007).

Leviton, A.E. and Banta, B.H. 1964. Midwinter reconnaissance of the herpetofauna of the Cape Region of Baja California, Mexico. Proceedings of the California Academy of Science, 4th series 30: 127-156.

McAfee, A. and Gilardi, J. 2000. Hypsiglena torquata: geographic distribution. Herpetological Review 31: 55.

McCranie, J.R. and Wilson, L.D. 2001. The herpetofauna of the Mexican State of Aguascalientes. Courier Forschungsinstitut Senckenberg 230: 1-57.

Murphy, R.W. and Ottley, J.R. 1984. Distribution of amphibians and reptiles on the islands in the Gulf of California. Annals of the Carnegie Museum 53: 207-230.

Rodríguez-Robles, J.A., Mulcahy, D.G. and Greene, H.W. 1999. Feeding ecology of the desert nightsnake, Hypsiglena torquata (Colubridae). Copeia 1999: 93-98.

Savage, J.M. 2002. The Amphibians and Reptiles of Costa Rica: A Herpetofauna between two Continents, between two Seas. University of Chicago Press, Chicago, Illinois.

Stebbins, R.C. 1985. A Field Guide to Western Reptiles and Amphibians. Second Edition. Houghton Mifflin Company, Boston, Massachusetts.

Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians. Third Edition. Houghton Mifflin Company, Boston, Massachusetts.

Tanner, W.W. 1944. A taxonomic study of the genus Hypsiglena. Great Basin Naturalist 5: 25-92.

Tanner, W.W. 1954. Additional note on the genus Hypsiglena with a description of a new subspecies. Herpetologica 10: 54-56.

Tanner, W.W. 1966. The night snakes of Baja California. Transactions of the San Diego Society of Natural History 14: 189-196.

Tanner, W.W. 1981. A new Hypsiglena from Tiburon Island, Sonora, Mexico. Great Basin Naturalist 14: 189-196.

Tanner, W.W. 1985. Snakes of western Chihuahua. Great Basin Naturalist 45: 615-676.

Vasquez-Díaz, J. and Quintero-Díaz, G.E. 2005. Anfibios y Reptiles de Aguascalientes. CONABIO y CIEMA, México, D.F. 318 pp.

Welsh, H.H. 1988. An ecogeographic analysis of the herpetofauna of the Sierra San Pedro Martir region, Baja California with a contribution to the biogeography of the Baja California herpetofauna. Proceedings of the California Academy of Science, 4th series 46: 1-72.

Werler, J.E. and Dixon, J.R. 2000. Texas Snakes: Identification, Distribution, and Natural History. University of Texas Press, Austin, Texas.

Zweifel, R.G. 1958. Results of the Puritan-American Museum of Natural History expedition to western Mexico. 2. Notes on the reptiles and amphibians from the Pacific coastal islands of Baja California. American Museum Novitates 1895: 1-17.


Citation: Hammerson, G.A., Frost, D.R., Santos-Barrera, G., Vasquez Díaz, J. & Quintero Díaz, G.E. 2007. Hypsiglena torquata. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 September 2014.
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