Abstract

ABSTRACT Although they have been considered distinct genera for over a century, ontogenetic analyses reveal that Triceratops and “Torosaurus” actually represent growth stages of a single genus. Major changes in cranial morphology—including the opening of parietal fenestrae and the elongation of the squamosals—occur rapidly, very late in Triceratops ontogeny and result in the characteristic ‘Torosaurus’ morphology. This report presents the results of a 10-year field study of the dinosaurs of the Hell Creek Formation in Montana and is based on a collection of over 50 specimens of Triceratops, including over 30 skulls, which have been amassed in that time, in addition to specimens from numerous other North American museums. This large sample of individuals reveals the full ontogenetic spectrum of Triceratops. The synonymy of Triceratops and ‘Torosaurus’ contributes to an unfolding view of extremely reduced dinosaur diversity just before the end of the Mesozoic Era.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.