Ammonite and inoceramid biostratigraphy and biogeography of the Cenomanian through basal Middle Campanian (Upper Cretaceous) of the Morondava Basin, western Madagascar

The stratigraphic distribution of ammonite and inoceramid faunas of the richly fossiliferous Cenomanian through basal Middle Campanian (Upper Cretaceous) succession of the Morondava Basin, western Madagascar, is provided, and biozonations, based on both groups, are established. The correlation with former schemes is discussed and the chronostratigraphic potential of each of the groups is evaluated, with reference to their biogeographic affinities. The study is based on entirely new field collections at four sections in the central and southern part of the Morondava Basin: (1) Antsirasira–Ampolipoly, (2) Mahaboboka, (3) Vohipaly, and (4) Manasoa-on-Onilahy. Geological logs and field details of these sections are also provided.