FOSSIL SEA-TURTLES FROM THE EARLY PLIOCENE BONE VALLEY FORMATION, CENTRAL FLORIDA

Four genera of cheloniid (Caretta, Chelonia, Eretmochelys, Lepidochelys) and one genus of dermochelyid (Psephophorus) sea turtles are recorded from the Bone Valley Formation of central Florida. The fossils derive from phosphate deposits of early Pliocene (late Hemphillian) age, 4.5-5 Ma. Although similar in age to fossils from the Yorktown Formation (Lee Creek Mine) in North Carolina, the Bone Valley sea turtle fauna appears to lack two genera found at Lee Creek (Syllomus, Procolpochelys) and contains one genus that is not found at Lee Creek (Eretmochelys). The Caretta from the two areas may not be conspecific. The fossil Chelonia, Eretmochelys, and Lepidochelys cannot be distinguished confidently from modern species, but conversely only the Lepidochelys appears obviously related to a particular modern species, L. kempi. This paper provides the first report of Eretmochelys in Pliocene deposits and the first association of Psephophorus with all living cheloniid genera except the Australian Natator. We suggest that shallow seas in the Bone Valley region provided rich feeding habitat for sea turtles in the early Pliocene in the same way that shallow water habitats in Florida and the Bahamas support a similar assemblage today.