Bullatosauria

Bullatosauria is an abandoned redundant clade, created in 1994 by paleontologist Thomas Holtz, to unite Ornithomimosauria with Troodontidae. Holtz in 1994 thought both groups were sister clades, but rejected this hypothesis in 1999. Most paleontologists now consider troodontids to be much more closely related to either birds or Dromaeosauridae than they are to ornithomimosaurs, causing the clade Bullatosauria to be abandoned.

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The name referred to the inflated (bulbous) sphenoid both groups shared. The definition could be given as: the clade containing the most recent common ancestor of Troodon and Ornithomimus and all its descendants. The concept is redundant given the existence of the concept Maniraptoriformes.

References

Holtz, T.J. jr, 1994, The phylogenetic position of the Tyrannosauridae. Implications for theropod systematics, Journal of Paleontology 68:1100-1117