Acrioceratidae is a family of heteromorph ammonites included in the Ancyloceratoidea comprising ancyloceratid-like forms that start off with a coiled juvenile section, followed by a straight or curved shaft ending in a hook.
The Acrioceratidae form a link, or evolutionary transition, between the loosely coiled Crioceratidae and the commonly tuberculate and heavy hooked Ancyloceratidae.
They differ from the ancestral Crioceratidae in that, like the Ancyloceratidae, they are truly heteromorphic (crioceratids aren't) with distinct growth phases.
The Treatise on Invertebrate Paleontology 1957, Part L, included Acrioceras, the nominate genus, in the Ancyloceratidae, with Dissimilites considered synonymous.
The Barremian heteromorph ammonite Dissimilites from northern Italy: taxonomy and implications.