The centrosaurine ceratopsid genus Styracosaurus is known from multiple specimens and a multigeneric bone bed in the upper 30 m of the Late Cretaceous Dinosaur Park Formation of southern Alberta, and a single specimen (S. ovatus) from approximately time equivalent sediments of the Two Medicine Formation of Montana. Key cranial elements (nasals and postorbitals) of Styracosaurus appear to undergo similar ontogenetic changes as documented in Centrosaurus. Although all adult-sized centrosaurines except Centrosaurus apertus are known to possess spike-like parietal ornamentation at the P3 position on the parietal, only Styracosaurus has the P4 ornamentation expressed as a well-developed spike. Styracosaurus shows intraspecific variation in the shape of the more anteriorly placed P5–P7 ornamentation that are either the typical unmodified crest-shaped epoccipitals of other centrosaurines or are developed as short spikes. S ovatus from Montana is retained as a valid species based on the autapomorphic convergence of the P3 spikes toward the midline.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 27 • No. 4