Jinzhousaurus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Ornithopoda > Iguanodontia > Ankylopollexia > Styracosterna > Hadrosauriformes > Hadrosauroidea

Overview: China’s famous Yixian Formation, in the province of Liaoning, is best known for its many feathered dinosaur specimens. There were, however, numerous non-feathered dinosaurs that also lived in the region. One of these was the ornithopod Jinzhousaurus, known from a nearly complete specimen preserved on a slab of Early Cretaceous-aged rock. Described in 2001, Jinzhousaurus was named after the city of Jinzhou, located close to where it was discovered. Studies done on the rock layers of the Yixian reveal that Jinzhousaurus would’ve lived in a vast woodland dotted by a series of lakes and active volcanoes. The environment appears to have been fairly temperate, so winters may’ve been relatively cold, at least by Cretaceous standards. Other famous dinosaurs found in the Yixian Formation include Psittacosaurus, Jeholosaurus, Sinosauropteryx, and Yutyrannus.

Jinzhousaurus grew to be a decently large ornithopod, measuring at least seven meters in length. It was similar in appearance to the famous Iguanodon, with some earlier studies even classifying it as a member of the family Iguanodontidae. While it was a member of the larger iguanodontian clade, it’s no longer seen as an iguanodontid today, with most agreeing it was probably more derived than Iguanodon. Jinzhousaurus was probably a basal member of the superfamily Hadrosauroidea, so it’s likely to have been more closely related to the true “duck-billed” dinosaurs. The creature did retain a handful of basal traits in common with Iguanodon, however. For instance, it appears to have had thumb spikes, likely used for foraging and physical defense. On more derived hadrosauroids, these spikes were absent. Jinzhousaurus probably fed on low to mid-level vegetation.