Euoplocephalus

Euoplocephalus; Temporal range: Late Cretaceous (Campanian),
	Skull of specimen TMP 1991.127.1
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Thyreophora
Clade:	†Ankylosauria
Family:	†Ankylosauridae
Subfamily:	†Ankylosaurinae
Tribe:	†Ankylosaurini
Genus:	†Euoplocephalus; Lambe, 1910
Type species
	†Euoplocephalus tutus; Lambe, 1902

Euoplocephalus (/juːˌɒploʊˈsɛfələs/ yoo-OP-loh-SEF-ə-ləs) is a genus of large herbivorous ankylosaurid dinosaurs, living during the Late Cretaceous of Canada. It has only one named species, Euoplocephalus tutus.

The first fossil of Euoplocephalus was found in 1897 in Alberta. In 1902, it was named Stereocephalus, but that name had already been given to an insect, so it was changed in 1910. Later, many more ankylosaurid remains were found from the Campanian of North America and often made separate genera. In 1971, Walter Coombs concluded that they all belonged to Euoplocephalus, which then make it one of the best-known dinosaurs. Recently, however, experts have come to the opposite conclusion, limiting the authentic finds of Euoplocephalus to about a dozen specimens. These include a number of almost complete skeletons, so nevertheless much is known about the build of the animal.

Euoplocephalus reached 5.3 metres (17 ft) in length and 2 metric tons (2.2 short tons) in body mass. Its body was low-slung and very flat and wide, standing on four sturdy legs. Its head had a short drooping snout with a horny beak to bite off plants that were digested in the large gut. Like other ankylosaurids, Euoplocephalus was largely covered by bony armor plates, among them rows of large high-ridged oval scutes. The neck was protected by two bone rings. It could also actively defend itself against predators like Albertosaurus, Daspletosaurus, and Gorgosaurus using a heavy club at the end of its tail.