Parksosaurus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Thescelosauridae > Thescelosaurinae

Overview: Named in honor of the Canadian paleontologist William A. Parks, known for naming the genus Parasaurolophus, Parksosaurus was a relatively small, bipedal ornithischian dinosaur. Fossils of the animal are known from the Horseshoe Canyon Formation, in what is now Alberta, Canada. It lived around sixty-nine to seventy million years ago, alongside other dinosaurs like Edmontosaurus, Saurolophus, Pachyrhinosaurus, Struthiomimus, Atrociraptor, and Albertosaurus. The latter two are likely to have preyed upon Parksosaurus. Lacking armor, speed was the only defense this dinosaur had. Parksosaurus was fairly lightly built, so it was likely at least somewhat agile. It sported slender, beaked jaws lined with relatively simple, leaf-shaped teeth. Narrower jaws imply a selective diet, so it may’ve preferred to go after specific, higher quality plants than to spend all its time grazing.

Parksosaurus belongs to a family of neornithischian dinosaurs called the Thescelosauridae, with it usually being placed specifically within the subfamily Thescelosaurinae. Thescelosaurus itself was a close relative. Most of them were small to medium-sized herbivores and primarily date to the Late Cretaceous, mainly in North America and Asia. Some of them lived in burrows, but we can’t be sure if this was the case with Parksosaurus itself. Fossils of Parksosaurus were first described in 1926 by Parks himself, who referred the bones to a supposed new species of Thescelosaurus. However, the fossils were later found to be from a distinct genus, leading to Charles M. Sternberg re-describing it as such in 1937. The two were quite similar in appearance, though Thescelosaurus was significantly larger than Parksosaurus, which was in turn larger than thescelosaurids like Oryctodromeus.