Cetiosauridae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of sauropod

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s which was first proposed by

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

in 1888. While traditionally a

wastebasket taxon Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...

containing various unrelated species, some recent studies have found that it may represent a natural clade. Alongside ''

Cetiosaurus ''Cetiosaurus'' () meaning 'whale lizard', from the Greek '/ meaning 'sea monster' (later, 'whale') and '/ meaning 'lizard', is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Period, living about 168 million years ago in what ...

'' from the Middle Jurassic of Britain, other taxa recently assigned to the family include ''

Lapparentosaurus ''Lapparentosaurus'' is a genus of sauropod dinosaur from the Middle Jurassic. Its fossils were found in Madagascar (Isalo III Formation). The type species is ''L. madagascariensis''. Discovery and naming In 1895 Richard Lydekker named a new s ...

'' from the Middle Jurassic of Madagascar, and ''

Patagosaurus ''Patagosaurus'' (meaning "Patagonia lizard") is an extinct genus of eusauropod dinosaur from the Middle-Late Toarcian of Patagonia, Argentina. It was first found in deposits of the Cañadón Asfalto Formation, which date to around 179 to 177&n ...

'' from the late Early-Middle Jurassic of Patagonia, which share

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

with ''Cetiosaurus'' that are not shared by other eusauropods. Additionally, at least one study has suggested that the

mamenchisaurids Mamenchisauridae is a family of sauropod dinosaurs belonging to Eusauropoda known from the Jurassic and Early Cretaceous of Asia and Africa. Some members of the group reached gigantic sizes, amongst the largest of all sauropods. Classification T ...

may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.

References

Eusauropoda Toarcian first appearances Late Jurassic extinctions Prehistoric dinosaur families {{sauropodomorph-stub