The Southern Durango spotted garter snake (''Thamnophis nigronuchalis'') is a species of snake of the family

Colubridae Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ever ...

. It is endemic to the state of

Durango Durango (), officially named Estado Libre y Soberano de Durango ( en, Free and Sovereign State of Durango; Tepehuán: ''Korian''; Nahuatl: ''Tepēhuahcān''), is one of the 31 states which make up the 32 Federal Entities of Mexico, situated in ...

, Mexico.

Description

This is a heavy-bodied, medium sized garter snake. It has an oval-shaped head with two

supralabial In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ( ...

scales, two preocular scales, and a distinct black blotch on the dorsal surface of its neck. It has 149-165 ventral and 63-70 caudal scales. Ventral scales are heavily pigmented, often forming an irregular black stripe. The dorsal pattern consists of rufous-colored spots outlined in black in 5-10 rows, with no dorsal or lateral stripes.

Taxonomy

Classification

While it is now considered a valid species, some authorities have classified this snake as a subspecies of the

narrow-headed garter snake The narrow-headed garter snake, ''Thamnophis rufipunctatus'', is a species of garter snake, endemic to the southwestern United States and adjacent northwestern Mexico. Its common names also include narrowhead garter snake and narrowhead watersna ...

under the name ''Thamnophis rufipunctatus nigronuchalis''.

Etymology

The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''nigronuchalis'' references the Latin word ''nigro'' meaning black, and ''nuchal'' meaning of the nape, and is derived from the black neck patch characteristic of the species.

Distribution and habitat

This snake is endemic to

state in Mexico, where it is found in wet meadows and riparian areas at altitudes of 8500–9000 feet. It appears to be restricted to high elevation drainage basins of the Sierra Madre Occidental.

Diet

This species has been documented to eat earthworms and amphibians, including ''

Rana pipiens ''Lithobates pipiens''Integrated Taxonomic Information System nternet2012''Lithobates pipiens'' pdated 2012 Sept; cited 2012 Dec 26Available from: www.itis.gov/ or ''Rana pipiens'', commonly known as the northern leopard frog, is a species of le ...

'' and '' Hyla'' species.

References

* {{Taxonbar, from=Q3519530 Reptiles described in 1957 Reptiles of Mexico Thamnophis