sentences:  Thomas Holtz found "Appalachiosaurus" to be an albertosaurine in 2004, but his more recent unpublished work locates it just outside Tyrannosauridae, in agreement with other authors.The other major subfamily of tyrannosaurids is the Tyrannosaurinae, including genera such as "Daspletosaurus", "Tarbosaurus" and "Tyrannosaurus".The close similarities between "Gorgosaurus libratus" and "Albertosaurus sarcophagus" have led many experts to combine them into one genus over the years.