Today for #FlatClamFriday Platyceramus cycloides (prev. P. platinus), the biggest, flattest clams that ever lived. During the Cretaceous these meter-wide XXXL pizzas of the sea thrived in in a variety of habitats, particularly at the bottom of the Cretaceous Interior Seaway that covered much of N. America. Exceptional specimens have been found approaching 3 m in size! They hosted vibrant collections of symbiotic fish, bivalves, shrimp and other creatures in their shells! #clamFacts