culebra de agua de cabeza angosta de Durango

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

This snake is endemic to Durango 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.

This species has been documented to eat earthworms and amphibians, including Rana pipiens and Hyla species.

The specific name 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.