An unusual hadrosaurid braincase from the Dinosaur Park Formation and the biostratigraphy of Parasaurolophus(Ornithischia: Lambeosaurinae) from southern Alberta
2009 (English)In: Canadian journal of earth sciences (Print), ISSN 0008-4077, Vol. 46, no 11, 791-800 p.Article in journal (Refereed) Published
The lambeosaurine hadrosaurid Parasaurolophus is known from rare occurrences in Campanian deposits of western North America. A previously undescribed large hadrosaurid braincase from the Dinosaur Park Formation (Alberta, Canada) is assigned to the genusParasaurolophus on the basis of several derived characters associated with the frontal–nasal articulation at the base of the crest. This identification is supported by two separate phylogenetic analyses, in which the specimen clusters with other more completely known Parasaurolophusexemplars. If correctly identified, the specimen represents the third and largest cranial specimen of the genus from the Late Cretaceous of Alberta. The specimen occurs in the same deposits as the holotype specimen of Parasaurolophus walkeri and may represent a late ontogenetic stage of this taxon. As opposed to a small frontal dome in the holotype of P. walkeri, the external contribution of the frontal to the skull roof is obliterated in the new specimen. If these hypothesized ontogenetic changes in the skull roof correlate with the size and posterodorsal development of the crest, as in other lambeosaurines, it suggests that the crest had not reached its full expression in the holotype. When placed into a detailed biostratigraphic context for the first time, the limited Parasaurolophus material from the Belly River Group is distributed in the lower half of the Dinosaur Park Formation at Dinosaur Provincial Park. This suggests thatParasaurolophus may be associated with the lower Centrosaurus–Corythosaurus assemblage zone and may have preferred more inland environments than other hadrosaurids, such asLambeosaurus and Prosaurolophus.
Place, publisher, year, edition, pages
NRC Research Press, 2009. Vol. 46, no 11, 791-800 p.
Evolutionary Biology Zoology
Research subject Biology with specialization in Evolutionary Organismal Biology
IdentifiersURN: urn:nbn:se:uu:diva-217234DOI: 10.1139/E09-050ISI: 000273027000001OAI: oai:DiVA.org:uu-217234DiVA: diva2:692570