Taxonomy
Sonora semiannulata was once broken up into five separate subspecies, based on the vast differences in color and patterning that the species displays, but recent research has shown that the various colors and patterns of ground snake interbreed indiscriminantly, making distinction between them impossible and thus not warranting subspecies status, though some sources still refer to them - using geography as a basis rather than morphology.
Read more about this topic: Western Ground Snake