The coevolution of rostral keratin cover and toothrow distribution in Mesozoic dinosaurs

Teeth evolved early in vertebrate evolution, and their morphology reflects important specializations in diet and ecology among species. The toothless jaws (edentulism) in extant birds likely coevolved with beak keratin, which functionally replaced teeth. However, extinct dinosaurs lost teeth multiple times independently and exhibited great variation in toothrow distribution and beak-like keratin structures. Here, we use facial jawbone surface texture as a proxy for rostral keratin covering and phylogenetic comparative models to test for the influence of facial keratin on toothrow distribution in Mesozoic dinosaurs. We find that the evolution of rostral keratin covering explains partial toothrow reduction but not jaw toothlessness. Toothrow reduction preceded the evolution of rostral keratin cover in theropods. Non-theropod dinosaurs evolved continuous toothrows despite rostral keratin cover (e.g., some ornithischians and sauropodomorphs). We also show that rostral keratin cover did not ..., , , # The coevolution of rostral keratin cover and toothrow distribution in Mesozoic Dinosaurs

## Description of the data and file structure

SM3.xlsx file data used for the analyses as detailed in Aguilar-Pedrayes et al. and cited references. We look at the evolutionary relationship between toothrow states and rostral keratin cover bone proxies in Mesozoic dinosaurs (Theropoda, Sauropodomorpha, Ornithischia) . Paper published in Proceedings of the Royal Society B.

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