Lower Cretaceous ammonites from the Neuquén Basin, Argentina: A new heteromorph fauna from the uppermost Agrio Formation

Abstract

Although the Agrio Formation (Valanginian-Early Barremian) yields rich ammonite faunas at many levels, the highest beds are very sparsely fossiliferous. However, intensive collecting over the years has yielded a sparse fauna of heteromorph ammonites that are completely new to Argentina. Three taxa are represented, Sabaudiella riverorum sp. nov., Curacoites rotundus gen. et sp. nov. and Hamulinites? sp. The fauna is placed in a new ammonite zone of Sabaudiella riverorum and dated as latest Hauterivian-Early Barremian.