Arctometatarsalia

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Arctometatarsalia Holtz 1994, emended 1996

Arctometatarasalia is a clade delineated in 1994 by Holtz, encompassing all maniraptorans exclusive of Dromaeosauridae, Avialae, and Oviraptorosauria, and primarily allying tyrannosaurs with a Troodontidae + Ornithomimosauria clade, Bullatosauria. Holtz based his assertion that this assemblage was holophyletic on the shared presence of an arctometatarsalian pes, in which the central metatarsal is tightly "pinched" or constricted at its proximal end. Holophyly of Arctometatarsalia is of doubtful validity, however, the homoplastic nature of the arctometatarsalian pes itself being but one reason.