Spinosauroidea

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Spinosauroids
Fossil range: Jurassic - Cretaceous

Life restoration of the megalosaurid Eustreptospondylus.

Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Order:	Saurischia
Suborder:	Theropoda
(unranked)	Tetanurae
Superfamily:	Spinosauroidea Stromer, 1915

Families

Megalosauridae
Spinosauridae

Synonyms

Megalosauroidea Huxley, 1889

Spinosauroidea is a superfamily of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. It is likely that megalosaurs are a family within this group.

[edit] Systematics

The name Megalosauroidea is sometimes used in place of Spinosauroidea. The superfamily Spinosauroidea was named in 1915 by Ernst Stromer. It is a younger synonym of Megalosauroidea if Megalosaurus is in the clade Spinosauroidea, which is the case in almost all modern phylogenetic analyses, and it is therefore redundant. Spinosauroidea was defined as a clade in 1998 by Paul Sereno as the node clade containing the common ancestor of Spinosaurus and Torvosaurus and all its descendants. Thomas Holtz in 2004 defined a stem clade with the same name containing all species closer to Spinosaurus than to Passer domesticus. Both clades within all probability include the clade Spinosauridae. The ICZN holds that even pure clade names (which do not yet have any governing body) should be replaced if having a traditional taxon suffix and being synonyms of ranked taxa at or below the superfamily level. However, in practice this recommendation has not been followed by in most paleontological literature, including Sereno 2005, which rejects the name Megalosauroidea on the grounds that it was historically paraphyletic (though Sereno retains other historically paraphyletic groups, such as Coelurosauria).