Description

The common garter snake stretches across most of the United States, from the Atlantic seaboard to the Pacific coast, and reaches north into Canada and Alaska. Among its many subspecies, the eastern form occupies the broadest area, while western variants such as parietalis and fitchi cover the Great Plains and the Rocky Mountain corridor. This study revives interest in a species that has been largely overlooked since the mid‑20th‑century revisions, aiming to map the western edge of the parietalis group and explore its connections to neighboring subspecies.

The authors trace a tangled taxonomic history, noting early 19th‑century descriptions, shifting locality records, and a series of synonymizations that have left many populations unnamed. By re‑examining museum specimens and field observations, they clarify the true type locality of parietalis and delineate its distinctive red markings compared with the more typical sirtalis pattern. Accompanied by detailed figures, the paper offers a clearer picture of how these snakes radiate across the plains and mountains, setting the stage for future ecological and genetic work.

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