Taxonomic utility of isolated ankylosaurian dinosaur teeth using traditional and geometric morphometrics with implications for ankylosaur palaeoecology

The presence of a basal cingulum, fluting, and overall size have been used to differentiate nodosaurid and ankylosaurid teeth for decades. The taxonomic utility of tooth morphology in ankylosaurs, however, has not been quantitatively tested. Additionally, new phylogenetic hypotheses recognize four ankylosaur families (Panoplosauridae, Polacanthidae, Struthiosauridae, and Ankylosauridae), rather than the traditional nodosaurid-ankylosaurid dichotomy. Understanding ankylosaur tooth variation could better help identify taxa with ambiguous phylogenetic affinities or allow isolated teeth to test palaeoecological questions like a potential extirpation of mid Cretaceous ankylosaurids from Laramidia. We analyzed a large sample of ankylosaur teeth using traditional and geometric morphometrics and investigated the utility of size and the presence of a cingulum and fluting for differentiating ankylosaur teeth. Morphometric analyses show that ‘nodosaurids’ had the greatest variation in tooth shape ..., , # Taxonomic utility of isolated ankylosaurian dinosaur teeth using traditional and geometric morphometrics with implications for ankylosaur palaeoecology

Dataset DOI: [10.5061/dryad.2547d7x3j](10.5061/dryad.2547d7x3j)

## Description of the data and file structure

We have included the raw dataset, as well as the tooth outline data and R code needed to replicate PCAs of traditional and outline morphometrics for leaf-shaped ornithischian teeth. We have data on over 300 ornithischian teeth associated or *in situ* with skulls of known species. We indicate whether the data and tooth images were collected in person by the authors, or from literature. We include the R code and tooth outlines for both the labial and lingual views of the teeth.

We also include complementary figures to the plots in the main text. \"Supplemental 7.docx\" indicates how principal compenents one and two contribute to the shapes in the morphospaces in our PCAs. We conducted linear regressions and residuals for the cr...,