The etymology of the generic name, Nerodia, is described elsewhere. The specific and subspecies names are the same, indicating this is considered the type-species; two Mexican subspecies, N. rhombifer werleri, and N. rhombifer blanchardi, respectively known locally as Tabasco and Tampico Diamond-backed water snakes, are found in northeast Mexico (The Mexican state of Tamaulipas: city of Tampico) and south along the Mexican Gulf and Atlantic coast (The Mexican state of Tabasco). The name rhombifer was assigned by the American herpetologist and physician Edward Hallowell (1808-1860) in 1852 when he first described the type species, and is derived from the Greek word ρομβος “rhombus” = a lozenge, i.e., a diamond-shaped article or marking. [...]