Craniodental functional evolution in sauropodomorph dinosaurs

David J. Button*, Paul M. Barrett, Emily J. Rayfield

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

8 Citations (Scopus)
248 Downloads (Pure)

Abstract

Sauropodomorpha included the largest known terrestrial vertebrates and was the first dinosaur clade to achieve a global distribution. This success is associated with their early adoption of herbivory, and sauropod gigantism has been hypothesized to be a specialization for bulk feeding and obligate high-fiber herbivory. Here, we apply a combination of biomechanical character analysis and comparative phylogenetic methods with the aim of quantifying the evolutionary mechanics of the sauropodomorph feeding apparatus. We test for the role of convergence to common feeding function and divergence toward functional optima across sauropodomorph evolution, quantify the rate of evolution for functional characters, and test for coincident evolutionary rate shifts in craniodental functional characters and body mass. Results identify a functional shift toward increased cranial robustness, increased bite force, and the onset of static occlusion at the base of the Sauropoda, consistent with a shift toward bulk feeding. Trends toward similarity in functional characters are observed in Diplodocoidea and Titanosauriformes. However, diplodocids and titanosaurs retain significant craniodental functional differences, and evidence for convergent adoption of a common adaptive zone between them is weak. Modeling of craniodental character and body-mass evolution demonstrates that these functional shifts were not correlated with evolutionary rate shifts. Instead, a significant correlation between body mass and characters related to bite force and cranial robustness suggests a correlated-progression evolutionary mode, with positive-feedback loops between body mass and dietary specializations fueling sauropod gigantism.

Original languageEnglish
Pages (from-to)435-462
Number of pages28
JournalPaleobiology
Volume43
Issue number3
Early online date22 May 2017
DOIs
Publication statusPublished - 1 Aug 2017

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