Deinonychosauria

Since the 1960s, the dromaeosaurids and troodontids have often been classified together in a group or clade named the Deinonychosauria, initially based primarily on the presence of a retractable second toe with sickle-claw. The name Deinonychosauria was coined by Ned Colbert and Dale Russell in 1969, and defined as a clade by Jaques Gauthier in 1986. Through the early 2000s, consensus among paleontologists was that dromaeosaurids were most closely related to the troodontids, and together with the troodontids, with deinonychosaurians in turn the sister taxon to avialans, and therefore the closest relatives of avialan birds.