Hadrosaurus

Hadrosaurus Temporal range: Late Cretaceous, ~80–78 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Possible Maastrichtian Record[1]
Reconstructed skeleton, Academy of Natural Sciences
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Ornithopoda
Family:	†Hadrosauridae
Subfamily:	†Hadrosaurinae
Genus:	†Hadrosaurus Leidy, 1858
Type species
†Hadrosaurus foulkii Leidy, 1858
Synonyms
Trachodon foulkii (Leidy, 1858) Lydekker, 1888 Hadrosaurus cavatus (Cope, 1871)[citation needed]

Hadrosaurus (/ˌhædrəˈsɔːrəs/; lit. 'bulky lizard') is a genus of hadrosaurid ornithopod dinosaurs that lived in North America during the Late Cretaceous Period in what is now the Woodbury Formation about 78-80 Ma. The holotype specimen was found in fluvial marine sedimentation, meaning that the corpse of the animal was transported by a river and washed out to sea.

They were large animals ranging from 7 to 8 m (23 to 26 ft) and 2 to 4 t (2.2 to 4.4 short tons). Most of the preserved elements are very robust, unusual traits in hadrosaurs. Hadrosaurus were ponderously-built animals equipped with keratinous beaks for cropping foliage and a specialized and complex dentition for food processing.

Hadrosaurus foulkii, the only species in this genus, is known from a single specimen consisting of much of the skeleton and parts of the skull. The specimen was collected in 1858 from the Woodbury Formation in New Jersey, US, representing the first dinosaur species known from more than isolated teeth to be identified in North America. Using radiometric dating of bivalve shells from the same formation, the sedimentary rocks where the Hadrosaurus fossil was found have been dated at some time between 80.5 and 78.5 million years ago. In 1858, the only known specimen became the first-ever dinosaur skeleton to be mounted. In 1991, H. foulkii became the official state dinosaur of New Jersey.^[2]