2012 Articles

A New Fossil Amiid from the Eocene of Senegal and the Persistence of Extinct Marine Amiids after the Cretaceous–Paleogene Boundary

O'Leary, Maureen A.; Sarr, Raphaël; Malou, Raymond; Sow, El Hadji; Lepre, Christopher J.; Hill, Robert V.

We report a new fossil amiid from Eocene rocks of West Africa representing the first record of this clade from Senegal. The new specimen has a maxilla that is very similar in size to that of Amia calva. It is distinctly smaller than reported remains of another West African Eocene taxon, Maliamia gigas. We tentatively refer the Senegal specimen to Vidalamiini because it has the large postmaxillary process diagnostic of this clade; however, it also exhibits anatomical features not previously described in extinct amiids. We recovered the specimen in rocks of the Lam-Lam Formation in Central-Western Senegal that we interpret to have been a shallow marine depositional environment. The occurrence of an Eocene marine amiid contradicts existing hypotheses that marine amiids were generally absent after the Cretaceous– Paleogene boundary having been replaced by freshwater taxa. Research completed since the initial discovery of Maliamia gigas indicates that this Eocene taxon was also found in shallow marine rocks.