The Fossil Cypraeidae of the Golden Gate Member, Tamiami Formation of Southern Florida: (Mollusca: Gastropoda: Cypraeidae)

Abstract

The first tropical hard corals, migrating from the Caribbean, established themselves along the rim of the Everglades Pseudoatoll in the mid to late Piacenzian Pliocene, 3.1-2.6 million years ago (hereinafter “mya”). The rim or perimeter delineated the pseudoatoll, a “U shaped” feature, open in the north, which ran east southeast from the Palm Beach Reef Tract through the Miami Beach Tract, curving to the southwest before linking with the Immokalee Reef Tract on the west coast of present day southern Florida. The pseudoatoll encompassed a very large depressional lagoon. The coral and coralline facies have been designated the Golden Gate Member (Golden Gate) of the Tamiami Formation. The Lower, Middle, Upper and Uppermost beds are equivalent in time with the Pinecrest and the Fruitville Members of the Tamiami Formation, with the middle and upper layers thickest as the warming of southern Florida progressed to its maximum during Fruitville time. Nine Cypraeidae species in three genera have been recorded from the Golden Gate: one in the Lower beds, three in the Middle beds, three in the Upper beds and two in the Uppermost beds. The pseudoatoll corals, coral reefs and associated molluscan fauna became extinct as the result of a catastrophic extinction event caused by rapid and severe cooling during the Piacenzian Pliocene and Gelasian Pleistocene crossover period, circa 2.6 mya. This event also marks the end of the Tamiami Formation.