Callizoniceras is a small, rather evolute, desmoceratid ammonite from the Lower Cretaceous, (U Barremian - L Albian), with strong branching ribs, a more or less rounded whorl section, deep constrictions, and a simple ammonitic sutures, included in the subfamily Puzosiinae. Two subgenera are recognized, C (Callizoniceras) from the upper Barremian and Aptian, in which ribs are regular and both ribs and constrictions are slightly sinuous, C (Wollemanniceras) from the Lower Albian in which ribs and straiae are irregular and main ribs are thick on in inner part, splitting into smaller riblets.
Graph IRI | Count |
---|