Individual and ontogenetic variation in theropod dinosaur teeth: A case study of Coelophysis bauri (Theropoda: Coelophysoidea) and implications for identifying isolated theropod teeth.

摘要

Isolated theropod teeth are useful data for paleogeographical and paleoecological studies, though ambiguous tooth morphotypes are frequently recovered from Late Cretaceous microfossil localities. It is not known if these morphotypes result from individual or ontogenetic variation. Eight hundred forty-eight teeth from twenty-three skulls of the Late Triassic (Carnian-Norian) theropod Coelophysis bauri from Ghost Ranch, New Mexico, were analyzed using statistical and multivariate analyses. Principle component and discriminant analyses show that, despite heterodontic morphology, teeth from premaxillae, maxillae, and dentaries, and teeth from small (juvenile) and large (adult) skulls occupy a similar morphospace and would not be mistakenly identified as new taxa. Teeth with longitudinal ridging only occur in small (juvenile) skulls also occupy the same morphospace as non-ridged teeth, and may be an ontogenetically controlled character of tooth morphology in C. bauri. Ridged tooth morphotypes from Late Cretaceous microfossil localities may be ontogenetic variants from known theropod taxa.