Bivalves are one of the major macroinvertebrate fossil groups of the Phanerozoic. Bivalves have occupied many aqueous habitats, and in doing this have undergone a steady, relatively unchecked increase in diversity (Figure 1). Thus, bivalves are one of the most useful fossil groups in paleoecology, both for environmental reconstruction as well as for deciphering patterns and processes of evolutionary paleoecology.