Vagaceratops


Vagaceratops is a genus of chasmosaurine ceratopsid dinosaur which lived during the Late Cretaceous period in what is now Alberta. Its fossils have been recovered from the Upper Dinosaur Park Formation. It is sometimes included in the genus Chasmosaurus as Chasmosaurus irvinensis instead of being recognized as its own genus.

History

In 2010, paleontologist Scott D. Sampson and colleagues named Vagaceratops, as well as Kosmoceratops and Utahceratops in the same article. These genera, which were considered unusual compared to typical members of their group, were part of a spate of ceratopsian discoveries in the early 21st century, when many new taxa were named.

Description

Vagaceratops was a medium-sized ceratopsian, reaching in length and weighing. It is known primarily from three fossil skulls. Although the general structure was typical of ceratopsids it has some peculiarities. The skulls are characterized by a reduced supraorbital horn, brow horns that are reduced to low bosses and a larger snout compared to related animals. Vagaceratops had smaller parietal fenestrae than most ceratopsids and had a strange configuration of epoccipitals. It possessed ten epoccipitals, eight of which were centrally flattened, curved forward and upward and fused together to form a jagged margin along the back of the frill. The frill was shorter and more square-shaped than other chasmosaurines, being wider than it was long.

Classification

Vagaceratops was named by Scott D. Sampson, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, and Alan L. Titus in 2010, and the type species is Vagaceratops irvinensis. This species was originally described as a species of Chasmosaurus in 2001. Its relationships remain debated. Vagaceratops has variously been allied with Kosmoceratops or with Chasmosaurus.
The cladogram below is the phylogeny of the Chasmosaurinae by Brown et al. :
Recently it has been suggested that Chasmosaurinae had a deep evolutionary split between a Chasmosaurus clade and a Pentaceratops clade. Vagaceratops was hypothesized to be the last member of the Chasmosaurus clade from northern Laramidia, with the last representative of the clade being its close relative ''Kosmoceratops.''