Protohadros

Protohadros means "first duckbill" and is the oldest known duck-billed dinosaur. Discovered in north-central Texas in 1995, Protohadros had hind legs longer than its front legs - allowing it to walk on two feet or on all fours.

Length	Up to 6 m (20 ft)
Weight	Up to 2 tons
Period	Late Cretaceous
Location	North America