Lanzhousaurus

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

Overview: Fossils attributed to this herbivore come from the Hekou Group, or a series of geological formations exposed in the Gansu Province of northwestern China. Studies of the Hekou suggest it’s most accurately dated to the Early Cretaceous. Recovered fossils included parts of the jaws, teeth, vertebrae, and parts of the pelvis, originally unearthed in the early 2000’s. Lanzhousaurus was given its scientific name in 2005, referencing the city of Lanzhou, located close to where the fossils were first reported. Other dinosaur fossils have been recovered from the Hekou Group, including those of some large sauropods and a few armored dinosaurs (both ankylosaurs and stegosaurs). All were likely occupying different ecological niches from one another. The latter group probably subsisted on low-level plants, the sauropods from tree branches, and Lanzhousaurus from a mix of both.

Lanzhousaurus is confidently classified as a member of the ornithopod clade Iguanodontia. It had a lot in common, appearance-wise, with Iguanodon itself. It was a sturdily built creature that walked both on all fours and as a biped. Many similar dinosaurs, including Iguanodon, sported thumb spikes, but we can’t be sure if Lanzhousaurus itself possessed them. Studies usually find Lanzhousaurus to have been less derived than Iguanodon, falling just outside the clade Hadrosauriformes. It appears to have been a decently large ornithopod, with suggested length estimates of nine or ten meters. Its most notable trait was its dentition. Iguanodonts often had impressive arrays of grinding teeth, but the teeth of Lanzhousaurus are notable for being among the largest of any herbivorous dinosaur. The jaws themselves were fairly robust, suggesting it could bite through very tough and woody plants.