Macrurosaurus

Macrurosaurus (meaning "large-tailed lizard") is the name given to a genus of dinosaur from the Early Cretaceous. It was a titanosauriform which lived in what is now England. The type species, M. semnus, was named in 1876. A second species, M. platypus, may also exist.

==History== The genus Macrurosaurus was named by Harry Govier Seeley in 1869 in his index of fossils from the Cambridge Greensand. In 1876 Seeley more thoroughly described the type species, Macrurosaurus semnus, making the name valid. The generic name is derived from Greek makros, "large", and oura, "tail". The specific name is derived from Greek semnos, "stately" or "impressive". A second species, M. platypus, from the Chalk Group of England, may also exist. Seeley in 1869 named it as a species of the ankylosaurid Acanthopholis but Friedrich von Huene named it as a second species of Macrurosaurus in 1956. It is known from the specimen CAMSM B55454-55461. In 1999 Xabier Pereda-Superbiola and Paul M. Barrett reviewed all Acanthopholis material. They concluded that all species were nomina dubia whose syntype specimens were composites of non-diagnostic ankylosaur and ornithopod remains. For example, the metatarsals included in the syntype series of Acanthopholis platypus are from a sauropod, but the remaining syntypes are not.