Bactrosaurus - Meaning: Club (spined or staff) Lizard

Bactrosaurus (bak-troh-sore-us) meaning "staff lizard" because it was the staff, or beginning, of a new line of dinosaurs was a herbivorous dinosaur that lived in east Asia in the late Cretaceous, 97 - 85 million years ago, making it one of the earliest known hadrosaurs (duck-billed dinosaurs).

Like many hadrosaurs, it could switch between bipedal and quadrupedal stances, but unusually it had large spines protruding from the vertebrae. It is also unusual within Lambeosaurinae for its absence of a cranial crest. A typical bactrosaurus would have been 6 metres (20 ft) long and 2 metres (7 ft) high when in the quadrupedal stance, and weighed 1100 - 1500 kg (2400 - 3300 lb), with an 80 cm (31 in) femur.

Six partial skeletons of this dinosaur have been recovered from Mongolia and China, the first of which was found in the same horizon as Archaeornithomimus. It was an early relative of Lambeosaurus, and shows a number of iguanodont-like features, including three stacked teeth for each visible tooth, small maxillary teeth, and an unusually powerful build for a hadrosaur.