Megalosauroidea

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Megalosauroids Fossil range: Jurassic - Cretaceous
Life restoration of the megalosaurid Eustreptospondylus.
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Order: Saurischia Suborder: Theropoda (unranked) Tetanurae Superfamily: Megalosauroidea Huxley, 1889
Families
Megalosauridae Spinosauridae
Synonyms
Spinosauroidea Stromer, 1915

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

The name Spinosauroidea is sometimes used in place of Megalosauroidea. 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. In practice this recommendation has not been followed by all paleontologists, particularly Sereno.

[edit] Taxonomy

Paul Sereno (1998, 2005) used Spinosauroidea as a clade (keeping the traditional superfamily suffix) containing the megalosaurids and the spinosaurids. While Spinosauroidea has priority of definition (Olshevsky 1995), there is as yet no official body regulating clade names. According to the ICZN rules for naming family-level taxa, the name Megalosauroidea has official priority when used as a superfamily taxon rank, having been implicitly named by Thomas Huxley in 1869, and therefore the name Megalosauroidea automatically replaces the name Spinosauroidea. This rule has been largely ignored in the 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). The classification of megalosauroids is as follows:

SUPERFAMILY MEGALOSAUROIDEA

• Family Megalosauridae
  • Piveteausaurus
    • Subfamily Megalosaurinae
      • "Brontoraptor"
      • Edmarka
      • Torvosaurus
      • Megalosaurus
      • Poekilopleuron
    • Subfamily Eustreptospondylinae
      • Streptospondylus
      • Piatnitzkysaurus
      • Eustreptospondylus
      • Magnosaurus
      • Dubreuillosaurus
      • Afrovenator
• Family Spinosauridae
  • Chilantaisaurus
  • Suchosaurus
    • Subfamily Baryonychinae
      • Baryonyx
      • Cristatusaurus
      • Suchomimus
    • Subfamily Spinosaurinae
      • Angaturama
      • Irritator
      • Siamosaurus
      • Spinosaurus