Ryan, Evans & Shepherd, 2012
Cretaceous Late Campanian
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Ceratopidae Centrosaurinae
Oldman Formation, Judith River Group (Wedge), Alberta, Canada
Coronosaurus brinkmani (Ryan, Evans & Shepherd, 2012) > Centrosaurus brinkmani (Ryan & Russell, 2005)
Coronosaurus refers to corona (Latin), for crown, and saurus (Latinized Greek), meaning “lizard”, in reference to the multiple occurrences of extra epiparietals that cover the posterior margin of the parietal, giving it a crown-like appearance.
Coronosaurus brinkmani (Ryan and Russell 2005).
Unless otherwise noted in Ryan and Russell (2005), all the ceratopsid material from BB 138 in Dinosaur Provincial Park, Alberta, and the Milk River Ridge bone bed (MRR BB) near Warner, Alberta, is referred to Coronosaurus brinkmani. Material is listed in Ryan (2003), a copy of which is on file with the Royal Tyrrell Museum of Palaeontology. Significant representatives of the parietal, postorbital, and supraorbitals include TMP 2002.68.3 (Ryan and Russell 2005, fig. 3a), TMP 2002.68.10 (Ryan and Russell 2005, figs. 3d, 3e), and TMP 2002.68.5 (Ryan and Russell
2005, fig. 3f), respectively.
Bone bed 138, Dinosaur Provincial Park, approximately 50 km from Brooks, Alberta, Canada (12 463090E, 5621680N (WGS 84)), Oldman Formation, 14.6 m below the contact with the Dinosaur Park Formation (645 m above sea level), referable to the Comrey sandstone (Eberth 2005). Additional referred specimens from the MRR BB near Warner, Alberta, approximately 180 km southwest of BB 138, are also from the Oldman Formation. Exact locality information of this bone bed is on file with the TMP.
As for the type and referred localities.
Adult-sized supraorbital horn cores are inflated (but not elongated as in Zuniceratops, chasmosaurines, Albertaceratops,and Diabloceratops) and project laterally overthe orbit; sub-adult-sized postorbital horn cores have an attenuated pyramidal shape with a slight lateral inflection of the distal one half; posterior parietal bar has a number of accessory epiparietal ossifications that fuse to the posterior an dorsal surfaces and through ontogeny develop as short spines that may fuse along their adjacent margins into larger, irregular masses. They contribute to the substance of P1 and, through fusion, form the composite epiparietal at the P2 loci. The P3 epiparietal is variably developed as a short tongue-likehook or tapered spike that is dorsolaterally oriented.
Coronosaurus brinkmani is distinguished from Centrosaurus apertus by key features of its cranial ornamentation, including the shape and orientation of the postorbital horn and parietal ornamentation at parietal locus 3, the shape of the parietal ornamentation at locus 2, and the possession of accessory parietal ossifications developed as short spines on the caudal parietal ramus. This species is restricted to the Oldman Formation of southern Alberta and is the oldest ceratopsid represented by diagnostic material in Canada. Phylogenetic analysis of the Centrosaurinae suggests that the development of spike-like ornamentation at the parietal locus 3 parietal locus is inversely related to the development of the P1 parietal ornamentation.