The foraminiferal family Orbitolinidae is represented in rocks of early Cretaceous through Eocene age. The genera Coskinolinoides, Iraqia, Simplorbitolina, Orbitolina, and Dictyoconus are included in the family because of the similarity of their wall structure and general test development. Genera previously assigned to this family which do not have the characteristic wall structure are removed from the family. Each of the genera assigned to the Orbitolinidae is diagnosed, on the basis of topotypes of the type species of each of the genera.

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