Prior to the discovery of "Dryptosaurus" in 1866, New World theropods were known only from some isolated theropod teeth discovered in Montana by Joseph Leidy in 1856. The discovery of this genus gave North American paleontologists the opportunity to observe an articulated, albeit incomplete, theropod skeleton. During the 19th century, this genus unfortunately became a wastebasket taxon for the referral of isolated theropod elements from across North America given that tyrannosauroids were not recognized as a distinct group of large theropods in the late 19th century, and numerous theropod species were assigned to it (often as "Lælaps" or "Laelaps") only to be later reclassified.