A juvenile chasmosaurine ceratopsid (Dinosauria, Ornithischia) from the Dinosaur Park Formation, Alberta, Canada

The triangular squamosal extends to the back of the parietals. Epiossifications are lacking, although the squamosal margin is thick and scalloped. The parietal has a pronounced midline sagittal crest.

Parietal fenestrae, if present, would have been narrow and elongate. There are only 18 maxillary tooth positions. The syncervical comprises three co-ossified, but distinct vertebrae.

Anterior caudal vertebrae support unfused caudal ribs. Ossified tendons in the neck, trunk, and sacrum do not extend into the tail. Hind limb proportions are comparable to those of adult ceratopsids.

The pedal unguals are distally acute. Skin impressions are similar to those of mature chasmosaurines. Phylogenetic analysis, if all characters are coded as they are seen, suggests that the specimen is a basal chasmosaurine.

When size or age dependent characters are recoded as ‘?,’ the specimen groups with other Chasmosaurus . These characters should only be used in phylogenetic analyses when all specimens are mature. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Currie, P. J., R. B. Holmes, M. J. Ryan, and C. Coy. 2016.

A juvenile chasmosaurine ceratopsid (Dinosauria, Ornithischia) from the Dinosaur Park Formation, Alberta, Canada. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1048348.