Protohadros

Protohadros was a primitive hadrosauroid ornithopod that lived during the early part of the Late Cretaceous in what is now Texas. Discovered in rocks of the Woodbine Formation, it provided critical early evidence for the transition from ancestral iguanodontian dinosaurs to advanced duck-billed hadrosaurs. Measuring about six to seven metres long, Protohadros was a bulky herbivore roughly the length of a minibus. It possessed robust jaws packed with interlocking columns of grinding teeth designed to pulverise tough fibrous plants. Its muzzle was noticeably downturned, which likely aided in cropping vegetation close to the ground. Although originally described as an ancestral true hadrosaur, subsequent anatomical studies place it just outside Hadrosauridae as a basal hadrosauroid.

Despite its generic name meaning first hadrosaur, it was later recognized as a non-hadrosaurid hadrosauroid.

Where and when

Protohadros lived in the Late Cretaceous, from 96 to 95 million years ago (Cenomanian age). Its remains come from United States, in the Woodbine Formation.

The numbers

Length 6.5 m (estimates run from 6 to 7 m). Mass about 1.2 t. Hip height about 2 m. That is 3.8 human-lengths, or 0.58 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Protohadros with a bus Place on the timeline