Lanzhousaurus (meaning "Lanzhou lizard") is a genus of ornithopod dinosaur. Lanzhousaurus lived in the Gansu region of what is now China during the Early Cretaceous (Barremian). A partial skeleton has been recovered from the Hekou Group. It was described by You, Ji and Li in 2005 and the type and only species is Lanzhousaurus magnidens. It's been estimated to be about 10 meters (33 feet) in length and 6 tonnes (6.6 short tons) in weight.

Dentition

The genus has been described as having "astonishingly huge teeth", among the largest for any herbivorous creature ever, which indicate it was a styracosternan iguanodont. The mandible, longer than one meter, suggests a very large size for the animal. Tooth enamel of this dinosaur was growing very rapidly.

Classification

In their 2020 reassessment of the hadrosauromorph Orthomerus, Madzia, Jagt & Mulder ran phylogenetic analyses of Iguanodontia. In their analyses, Lanzhousaurus was recovered as a non-hadrosauriform styracosternan member of the Ankylopollexia, similar to the 2005 description by You, Ji & Li. The results of their phylogenetic analyses are shown in the cladogram below: