Pectinida is a taxonomic order of large and medium-sized saltwater clams, marine bivalve molluscs, commonly known as scallops and their allies.[1] It is believed that they began evolutionarily in the late Middle Ordovician epoch; many species, of course, are still extant.[2]
In 2010 a new proposed classification system for the Bivalvia was published by Bieler, Carter & Coan, revising the classification of the Bivalvia, including the order Pectinida.[3]