The dentition of tyrannosauroid theropods: a review

Abstract

Tyrannosauroidea is a clade of early-diverging carnivorous coelurosaur theropods known from the Middle Jurassic to Late Cretaceous that includes the eponymous Tyrannosaurus rex and its closest relatives. One of the most notable diagnostic features of the group is the heterodont dentition. The dentition of tyrannosauroids has been extensively studied from diverse lines of inquiry, making it one of the most thoroughly studied among non-avian dinosaurs. In this paper, we summarize the state of research on tyrannosauroid dentition from 234 publications. Historically, the study of external anatomy has been the main analysis object, and this information has been appropriate for the taxonomic assignment of isolated teeth. Since the 1980’s, the methodologies used in the study of teeth have diversified, and today, data on morphometric variation, histology, isotopes preserved in enamel and dentine, biomechanical properties of crowns and denticles, dental replacement, and wear have complemented our knowledge about the paleobiology of the group. In a brief comparison based on published data between the dental anatomy of Megaraptora and Tyrannosauroidea, several attributes are shared between them, which can be considered an indication of possible affinity between the two clades. Most dental studies have typically focused on tyrannosaurids, especially Albertosaurus spp. and Tyrannosaurus spp. However, they show great potential for these methodologies to contribute to our understanding of the paleobiology of other tyrannosauroids, as well as provide information for paleontological studies applied to other archosaurs.