A new specimen of Chasmosaurus belli (Ornithischia: Ceratopsidae), a revision of the genus, and the utility of postcrania in the taxonomy and systematics of ceratopsid dinosaurs Author Maidment, Susannah C. R. Author Barrett, Paul M. text Zootaxa 2011 2963 1 47 journal article 10.5281/zenodo.278172 5bc8fcc0-d9a3-4036-ba87-e75e60779208 1175-5326 278172 Chasmosaurus belli Lambe, 1902 Monoclonius belli Lambe 1902 : 59 Monoclonius canadensis Lambe 1902 : 63 Ceratops belli Hatcher et al. 1907 : 97 Ceratops canadensis Hatcher et al. 1907 : 97 Protorosaurus belli Lambe 1914: 131 Chasmosaurus belli Lambe 1914: 149 Eoceratops canadensis Lambe 1915 : 2 Chasmosaurus kaiseni Brown 1933 : 2 Chasmosaurus brevirostris Lull 1933 : 94 Chasmosaurus canadensis Lehman 1989 : 139 Amended diagnosis. Taxon displaying the combination of characters unique to the genus Chasmosaurus along with the following features: (1) parietal posterior bar bearing no median emargination and is nearly straight so that it forms a ‘T’ shape with the parietal median bar; (2) lateral pair of epiparietals large and triangular; others, when preserved, are smaller (after Godfrey & Holmes 1995 ). Both characters are autapomorphic for C. belli within Chasmosaurus . Holotype . CMN 491, a partial parietal. Although fragmentary, the holotype is diagnostic based on the combination of generic character 4, and specific character 1, a combination not observed in any other chasmosaurine. Distribution. Middle and upper beds of the Dinosaur Park Formation, Alberta, Canada ( Ryan & Evans 2005 ). Referred specimens. CMN 2245; AMNH 5402; ROM 843; YPM 2016; NHMUK R4948 (after Ryan & Evans 2005 ). The NHMUK specimen is referred to Chasmosaurus because it possesses characters 1, 3, 4 and 5 from the diagnosis of Chasmosaurus (above); it is referred to C. belli because it possesses character 1 from the diagnosis of C. belli (above). Specimens removed from C. belli . ROM 839 was referred to C. belli by Ryan and Evans (2005) and Longrich (2010) , but is not diagnosable to species level based on the amended diagnosis presented here and represents Chasmosaurus sp.