[D] Chasmosaurus irvinensis [Su]
Describer
Holmes, Forster, Ryan, and Shepherd, 2001
Time
Cretaceous Late Campanian
Classification
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Ceratopidae Chasmosaurinae
Diet
Herbivore
Fossilsite
Dinosaur Park Formation, Alberta, Canada
Fall Under
Vagaceratops irvinensis
Info
Skull
Vagaceratops irvinensis (Sampson, Loewen, Farke, Roberts, Forster, Smith & Titus 2010) > Chasmosaurus irvinensis (Holmes, Forster, Ryan, and Shepherd, 2001)
Chasmosaurus irvinensis (sp. nov.) is distinguished from other species of this genus by the possession of a broad snout, absence of a brow horn (the position of which is occupied by a pit or rugosities suggestive of bone resorption), broadly rounded and open jugal notch, subrectangular squamosal, straight posterior parietal bar bearing 10 epoccipitals, eight of which are flattened, strongly curved anterodorsally, and nearly indistinguishably coossified to their neighbours, and small, transversely oriented parietal fenestrae restricted to the posterior portion of the frill.
This species, restricted to the upper part of the Dinosaur Park Formation, is significantly younger than the other recognized Canadian Chasmosaurus species, Chasmosaurus belli and Chasmosaurus russelli. Phylogenetic analysis shows that Chasmosaurus irvinensis is most closely related to the other Canadian Chasmosaurus species and more distantly related to Chasmosaurus mariscalensis from Texas. Chasmosaurus irvinensis is named after the town of Irvine in southeast Alberta.
Known material
Three skulls, one amost complete, postcrania. Holotype: CMN [formerly NMC] 41357, a skull and articulated skeleton. Discoverd by Luke Lindoe, southwest of Irvine, southern Alberta in 1958 onder the direction of Wann Langston Jr. a former Museum palaeontologist. The skull of CMN 41357 was reconstructed and cast by Doug Watson under the direction of Robert B. Holmes.
Additonal material
Also from the Dinosaur Park Formation, near the viallge of Onefour, northwest of Idesleigh, southeastern Alberta consist out of: RTMP 87.451, a dorsoventrally crushed skull lacking the mandible, most of the caudal parietal bar, most of the right squamosal, and the distal tip of the right ungual. RTMP 98.102.8, fragmentary skull with an almost complete posterior parietal bar.
After its excavation, the dinosaur skeleton was enclosed in a plaster field jacket and transported to the Museum\\\\\\\'s collections in Ottawa, where it sat unopened for decades.
Holmes, Forster, Ryan, and Shepherd, 2001
Time
Cretaceous Late Campanian
Classification
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Ceratopidae Chasmosaurinae
Diet
Herbivore
Fossilsite
Dinosaur Park Formation, Alberta, Canada
Fall Under
Vagaceratops irvinensis
Info
Skull
Vagaceratops irvinensis (Sampson, Loewen, Farke, Roberts, Forster, Smith & Titus 2010) > Chasmosaurus irvinensis (Holmes, Forster, Ryan, and Shepherd, 2001)
Chasmosaurus irvinensis (sp. nov.) is distinguished from other species of this genus by the possession of a broad snout, absence of a brow horn (the position of which is occupied by a pit or rugosities suggestive of bone resorption), broadly rounded and open jugal notch, subrectangular squamosal, straight posterior parietal bar bearing 10 epoccipitals, eight of which are flattened, strongly curved anterodorsally, and nearly indistinguishably coossified to their neighbours, and small, transversely oriented parietal fenestrae restricted to the posterior portion of the frill.
This species, restricted to the upper part of the Dinosaur Park Formation, is significantly younger than the other recognized Canadian Chasmosaurus species, Chasmosaurus belli and Chasmosaurus russelli. Phylogenetic analysis shows that Chasmosaurus irvinensis is most closely related to the other Canadian Chasmosaurus species and more distantly related to Chasmosaurus mariscalensis from Texas. Chasmosaurus irvinensis is named after the town of Irvine in southeast Alberta.
Known material
Three skulls, one amost complete, postcrania. Holotype: CMN [formerly NMC] 41357, a skull and articulated skeleton. Discoverd by Luke Lindoe, southwest of Irvine, southern Alberta in 1958 onder the direction of Wann Langston Jr. a former Museum palaeontologist. The skull of CMN 41357 was reconstructed and cast by Doug Watson under the direction of Robert B. Holmes.
Additonal material
Also from the Dinosaur Park Formation, near the viallge of Onefour, northwest of Idesleigh, southeastern Alberta consist out of: RTMP 87.451, a dorsoventrally crushed skull lacking the mandible, most of the caudal parietal bar, most of the right squamosal, and the distal tip of the right ungual. RTMP 98.102.8, fragmentary skull with an almost complete posterior parietal bar.
After its excavation, the dinosaur skeleton was enclosed in a plaster field jacket and transported to the Museum\\\\\\\'s collections in Ottawa, where it sat unopened for decades.