Dental Morphologies in Gartersnakes (Thamnophis) and Their Connection to Dietary Preferences

We examined morphological variation in tooth structure in four populations of garter snakes (genus Thamnophis) with diverse feeding habits and tested the hypothesis that morphological homoplasy evolved in the malacophagous predators Thamnophis ordinoides and Thamnophis elegans terrestris. Although l...

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Bibliographic Details
Published in:Journal of herpetology 2009-06, Vol.43 (2), p.252-259
Main Authors: Britt, E. J, Clark, A. J, Bennett, A. F
Format: Article
Language:English
Subjects:
Adaptations
Animal morphology
Garters
Herpetology
Mandible
Maxilla
MORPHOLOGY
Predators
Slugs
Snails
Snakes
Teeth
Thamnophis
Thamnophis couchii
Thamnophis elegans elegans
Thamnophis elegans terrestris
Thamnophis ordinoides
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Summary:We examined morphological variation in tooth structure in four populations of garter snakes (genus Thamnophis) with diverse feeding habits and tested the hypothesis that morphological homoplasy evolved in the malacophagous predators Thamnophis ordinoides and Thamnophis elegans terrestris. Although long, slender teeth are typical in Neotropical colubrid snake species that prey on slugs and snails, this morphological feature did not occur in T. ordinoides and T. e. terrestris relative to closely related garter snakes (the diet generalist Thamnophis elegans elegans and piscivore Thamnophis couchii). However, we did find pronounced posterior ridges located on the posterior maxillary teeth in the two slug predators but not in the generalist feeders. The evolutionary origin and functional advantage of these ridges has yet to be identified. The fish specialist T. couchii has many morphological features characteristic of adaptations for piscivory, such as long, sharper teeth and elongated mandible bones.
ISSN:0022-1511
1937-2418
DOI:10.1670/08-109R1.1