Dentitional surface features in snakes (Reptilia: Serpentes)

The complexity of snake tooth morphology is more varied than has been recognized in functional, evolutionary, or taxonomic studies. We surveyed a broad sample of species across taxonomic groups to document and summarize the variation present. Our survey included a scoring of dentitional features of 1169 specimens representing 611 species of snakes on four dentiferous bones (dentary, pterygoid, palatine, maxilla). Besides presence or absence of teeth on these bones, we ranked the tooth type on each bone on the basis of a four category system: basic, furrowed, grooved, or hollow tooth. Basic teeth, without surface recesses or grooves, were the most common tooth type. Hollow teeth (fangs) were found most commonly on the maxilla and grooved teeth were often adjacent. Grooved teeth, when present, were found only on the maxilla although teeth with furrows, shallow creases in the surface enamel, were found in low numbers on the dentary, pterygoid, and palatine. Teeth exhibited further specializations, including multiple grooves, basal reinforcing ridges, development of a blade-like design, variation in the degree to which the secondary groove in hollow teeth might be in evidence, and variation in the position of the groove along the shaft of the tooth.