 And, eventually, the "skull capsule" in troodontids and ornithomimosaurs was found to be an example of convergent evolution, causing the clade Bullatosauria to be abandoned.Holtz was also a key figure in the discovery that tyrannosauroids were not carnosaurs, as had been previously believed by most palaeontologists, but rather large coelurosaurs.By being one of the very first scientists to theorise this, Holtz contributed greatly to the debunking of a monophyletic Carnosauria.