Dental morphology in snakes is highly variable, shaped by the life history and feeding habits of different species. Many venomous snakes exhibit heterodonty—a condition where teeth vary in shape—often featuring specialized fangs for venom delivery. In contrast, non-venomous species typically display homodonty, where all teeth share a uniform shape. However, homodonty and heterodonty exist on a continuum, with many snake species exhibiting intermediate dentition patterns.

Snake dentition is further complicated by factors such as fang position, enlargement, and the presence or absence of grooves. However, the classification of these traits remains ambiguous, with significant variation in terminology and definitions among researchers.

The Western whip snake (Hierophis viridiflavus) has traditionally been classified as an opisthoglyphous species, meaning it possesses rear-positioned, grooved fangs. Despite being considered non-venomous, some reports suggest potential envenomation effects in humans bitten by this species. In the absence of detailed studies on its oral glands and saliva composition, a recently accepted paper in Acta Herpetologica investigates its dentition through optical and electron microscopy. The study examined 17 disarticulated skeletons housed at the Museum of Geology and Paleontology, University of Turin.

In all specimens, the last two maxillary teeth were notably distinct in shape and size but lacked true grooves. Based on these findings, the authors challenge the classification of H. viridiflavus as opisthoglyphous, as it does not possess the anterolateral grooves traditionally required for this designation. Instead, they propose defining the species as opisthomegadont, placing it within the broader category of "non-front-fanged snakes."

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