Date Thesis Awarded

4-2020

Document Type

Honors Thesis

Degree Name

Bachelors of Science (BS)

Department

Biology

Advisor

S. Laurie Sanderson

Committee Members

Rowan Lockwood

John Swaddle

Paul Heideman

Abstract

Without the direct evidence of stomach content, the diet of fossil organisms can be difficult to determine. In this study, we sought to reconstruct the diet of the mosasaur species Clidastes liodontus utilizing a morphospace of skull morphology featuring squamates within the proposed clade Toxicofera. I collected 11 linear measurements of skull bones considered important for manipulating food in extant squamates, including anguimorphs, snakes, and iguanids. I measured 198 specimens representing 89 species from collections in the National Museum of Natural History, the Sternberg Museum of Natural History, the Peabody Museum of Natural History, and the Alabama Museum of Natural History. I then used multivariate statistical analyses to develop a morphospace which allowed us to categorize the toxicoferan squamates on the basis of their diet and infer diet in C. liodontus. Phylogenetically, PCs of the four infraorders show that size of the organisms and pterygoid morphology accounts for most of the variation in the data. Based on pterygoid morphology, mosasaurs act as an intermediate between snakes and the other lizard infraorders. Based on morphospaces of mosasaurs and snakes, aquatic ectotherm specialists have more pterygoid teeth, a higher percent of the pterygoid occupied by teeth, and a more spread out distribution of pterygoid teeth. Using the snake and mosasaur morphospace, C. liodontus group uniquely among mosasaurs. Other mosasaurs group with terrestrial ectotherm specialists/generalists, whereas C. liodontus groups with aquatic ectotherm specialists, suggesting a fish-based diet, much like that of modern sea snakes.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License

Available for download on Saturday, May 07, 2022

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