Tyrannoraptora is a clade defined as "all descendants of the last common ancestor of Tyrannosaurus rex and Passer domesticus (the house sparrow)". The clade was named in 1999 by the American paleontologist Paul Sereno, though in his original concept had Tyrannosauroidea being the sister taxon to Pennaraptora. Phylogenetic analyses have since, however, found the group also encompasses Compsognathidae, Ornithomimosauria, Alvarezsauroidea, and Therizinosauria. Thus tyrannoraptorans are divided into tyrannosauroids and maniraptoromorphs.