Walker (1968) was first to use the taxon Crocodylomorpha, which is here considered a spelling variant of Hay’s (1930) taxon Crocodylomorphi. Many references in the literature cite Wlaker (1970) as the origin of this taxon name. The name was first used explcitly as a clade by Clark (in Benton and Clark 1988; sensu Walker 1968). Despite its widespread use, the taxon seems never to have been defined.
The active definition is stem-based so that Crocodylomorpha includes all taxa closer to extant crocodilians than to any other recognized suchian subclade. A number of external specifiers are included to ensure stability of taxonomic content in the face of shifting relationships immediately outside the clade. A potential synonmym is Crocodylia in its traditional sense (e.g. Steel 1973), although Crocodylia has never been given a phylogenetic definition with this content.