Crocodyliformes is a suborder of crurotarsan archosaurs named by Hay, 1930, the group often traditionally referred to as "crocodilians." Crocodyliformes were referred to as a clade by Clark in 1988, in a paper written by James M. Clark and Michael J. Benton in which they argued that all traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for natural groups comprising all living members of any given lineage. This posed a problem for the crocodilians, because the name Crocodylia, while used in various ways by various scientists, had always included not only living crocodilians but many of their extinct ancestors known only from the fossil record.