Macrurosaurus (meaning "large-tailed lizard") is the name given to a genus of dinosaur from the Early Cretaceous.

[2][3] The genus Macrurosaurus was named by Harry Govier Seeley in 1869 in his index of fossils from the Cambridge Greensand.

They concluded that all species were nomina dubia whose syntype specimens were composites of non-diagnostic ankylosaur and ornithopod remains.

[7] The first was acquired by the Woodwardian Museum from William Farren who had it dug up at Coldhams Common near Barnwell.

Seeley, acting on the presumption that both finds belonged to the same species if not individual, combined the two series into one tail of about 4.5 metres length.

Other fragmentary fossils from England (Acanthopholis platypus),[2] France and Argentina have later been referred to Macrurosaurus[8] but the identity is today doubted.