Alocolytoceras is a lytoceratid ammonite with whorls that pass during growth from round to oval, rounded-quadrate, or compressed; with  about 19 deep constrictions per whorl, with as many as 21 sharp ribs in between.
Alocolytoceras is a lytoceratid ammonite with changing whorls that transition from circular to elliptical, rounded-quadrate, or compressed; it has approximately 19 deep constrictions per whorl and up to 21 sharp ribs between them.