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Bactrosaurus kysylkumensis

Bactrosaurus
Temporal range: Late Cretaceous, 70 Ma
Bactrosaurus johnsoni 1.jpg
Partial B. johnsoni skeleton
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Superfamily: Hadrosauroidea
Genus: Bactrosaurus
Gilmore, 1933
Type species
Bactrosaurus johnsoni
Gilmore, 1933
Species
  • B. kysylkumensis? (Riabinin, 1931 [originally Cionodon])
  • B. johnsoni Gilmore, 1933

Bactrosaurus (/ˌbæktrˈsɔːrəs/; meaning "Club lizard," "baktron" = club + sauros = lizard) is a genus of herbivorous dinosaur that lived in east China during the late Cretaceous, about 70 mya, though some Bactrosaurus fossils have been dated back to 90 mya. The position Bactrosaurus occupies in the Cretaceous makes it one of the earliest known hadrosauroids, and although it is not known from a full skeleton, Bactrosaurus is one of the best known of these forms of hadrosaurs predecessors.

A typical Bactrosaurus would have been 6 metres (20 ft) long and 2 metres (6.6 ft) high when standing on all fours, and weighed 1.1 to 1.5 tonnes (2,400 to 3,300 lb), with an 80 centimetres (2.6 ft) femur.

It was an early relative of Lambeosaurus, perhaps a predecessors, as it 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. It shows features intermediate between those of the two main hadrosaurid groups, and may represent an ancestral form that evolved from an earlier iguanodontid dinosaur.

Bactrosaurus was originally described as lacking a crest, which would be typical for an iguanodont, but anomalously primitive for a lambeosaurine like itself. However subsequent study of Bactrosaurus remains uncovered pieces of what appear to be the base of an incompletely preserved crest.


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