Extreme cranial ontogeny in the upper cretaceous dinosaur pachycephalosaurus.

ABSTRACT:

Background

Extended neoteny and late stage allometric growth increase morphological disparity between growth stages in at least some dinosaurs. Coupled with relatively low dinosaur density in the Upper Cretaceous of North America, ontogenetic transformational representatives are often difficult to distinguish. For example, many hadrosaurids previously reported to represent relatively small lambeosaurine species were demonstrated to be juveniles of the larger taxa. Marginocephalians (pachycephalosaurids + ceratopsids) undergo comparable and extreme cranial morphological change during ontogeny.

Methodology/principal findings

Cranial histology, morphology and computer tomography reveal patterns of internal skull development that show the purported diagnostic characters for the

SUBMITTER: Horner JR 

PROVIDER: S-EPMC2762616 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature