The utility of tooth enamel microstructure in identifying isolated dinosaur teeth

Abstract

Hwang, S.H. 2010: The utility of tooth enamel microstructure in identifying isolated dinosaur teeth. Lethaia, Vol. 43, pp. 307–322. The identification of isolated dinosaur teeth is frequently an uncertain process because dinosaur teeth are simple in morphology compared to those of mammals. Teeth among genera and species within major dinosaur clades are often identical, and damage or abrasion of teeth further complicates their identification. To aid diagnosis of isolated teeth, systematic descriptions of dinosaur teeth have been compiled, and quantitative morphometric identification methods have also been developed. However, these aids work best with relatively intact teeth. Enamel microstructure, in contrast, can be used to identify the minutest of tooth fragments as long as the entire enamel thickness, often <100 μm, is preserved. In addition, enamel microstructure can be used to differentiate isolated teeth that are similar in morphology but have different enamel, such as ankylosaur and posterior pachycephalosaurid or basal theropod and tyrannosaurid teeth. To evaluate the efficacy of enamel microstructure as an identification tool, nine isolated dinosaur teeth, specimens originally identified as ‘Carnosauria’ indet., Theropoda indet., Nanotyrannus sp., Tyrannosauridae indet., Troodontidae indet., Pachycephalosauridae indet., Hadrosaurinae indet. and cf. Thescelosaurus sp., were sectioned and their enamel examined using scanning electron microscopy. Upon inspection of their enamel microstructure, three of the specimens could be identified to genus, and the taxonomic identity of all the specimens were better understood. While enamel microstructure may not always constrain the identity of an indeterminate tooth to the generic or species level, it usually allows for a more accurate identification. □Dinosaur teeth, enamel microstructure, taxonomic identification, microfossils.