Dental measures of extant lizards and fossil reptiles

Procolophonoids are hypothesized to be some of the first highly
specialized herbivores to evolve in the aftermath of the end-Permian
extinction. Hypotheses of procolophonoid diet are based on their unique
dentitions: bulbous, multicuspid, differentiated teeth, specialized for
feeding on fibrous plant matter. However, these conclusions are largely
based on qualitative descriptions, and there has yet to be a broadscale,
quantitative comparison of this group of fossil reptiles to modern ones.
In our study, we use relatively simple measures of tooth shape and linear
discriminant analysis (LDA) to predict dietary ecology from tooth
dimensions and phylogenetic MANOVA to test for significant differences in
tooth shape for different diets. We find that procolophonids are largely
predicted as herbivorous but occupy different ecological niches from
modern lizards and that simple methods return relatively similar results
as complex methods. We hypothesize that the different mechanical
challenges of Triassic-age flora produced a different 'kind' of
herbivorous tooth from those observed in extant lizards, like those in
procolophonids.