 This group includes the well known mussels, scallops, pen shells, and oysters.It also includes the only members of the class bivalvia to have rudimentary eyes.The cladogram is based on molecular phylogeny using mitochondrial (12S, 16S) and nuclear (18S, 28S, and H3) gene markers by Yaron Malkowsky and Annette Klussmann-Kolb in 2012.