Cryptoclidia is a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

plesiosaur The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared ...

s. Cryptoclidia was named and defined as a node clade in 2010 by Hilary Ketchum and

Roger Benson Roger is a given name, usually masculine, and a surname. The given name is derived from the Old French personal names ' and '. These names are of Germanic languages, Germanic origin, derived from the elements ', ''χrōþi'' ("fame", "renown", " ...

: the group consisting of the

last common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...

of ''

Cryptoclidus ''Cryptoclidus'' ( ) is a genus of plesiosaur reptile from the Middle Jurassic Period (geology), period of England, France, and Cuba. Discovery ''Cryptoclidus'' was a plesiosaur whose specimens include adult and juvenile skeletons, and remai ...

eurymerus'' and ''

Polycotylus ''Polycotylus'' is a genus of plesiosaur within the family Polycotylidae. The type species is ''P. latippinis'' and was named by American paleontologist Edward Drinker Cope in 1869. Eleven other species have been identified. The name means 'much- ...

latipinnis''; and all its descendants. The following

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

follows an analysis by Benson & Druckenmiller (2014).

References

Plesiosaurs {{plesiosaur-stub