Abstract
AbstractThe present contribution illustrates the type material of the Lower Cretaceous ammonoids Ptychoceras aequicostatus Gabb, 1864 (type species of Helicancylus Gabb, 1869) and Hamiticeras pilsbryi Anderson, 1938 (type species of Hamiticeras Anderson, 1938). The typification and taxonomic validity of both genera are clarified, and the affinities with coeval Acrioceratidae are discussed. Their stratigraphic range is investigated with implications for correlation between northern Pacific and European ammonoid scales.
Publisher
Cambridge University Press (CUP)
Reference63 articles.
1. Dauphin, L. , 2002, Litho-, bio-, et chronostratigraphie comparées dans le Bassin Vocontien à l'Aptien [Ph.D. thesis]: Lille, France, Université Lille, 451 p.
2. New and less known Barremian-Albian ammonites from Colombia;Kakabadze;Scripta Geologica,1997
3. A revised chronostratigraphic framework for the Aptian of the Essaouira-Agadir Basin, a candidate type section for the NW African Atlantic Margin
4. Zonation of the Cretaceous of central Colombia by ammonites;Etayo-Serna;Publicaciones Geologicas Especiales del Ingeominas,1979