Taxonomy and Paleoecology of a New Species of Sphenia (Bivalvia; Myidae) from the Pleistocene of Florida

Abstract

The new species, Sphenia tumida, is described from the Pleistocene of Flagler County, Florida, an occurrence believed to represent the last known appearance of the genus in the western Atlantic waters immediately adjacent to the North American continent. Taxonomic characters of the genus are reviewed, as are the geographic distribution and ecology of living species and the geologic distribution of fossil species in eastern North America. Paleoecological inferences drawn from this occurrence suggest a progressive shallowing of the Pamlico embayment or lagoon in Flagler County, with a proportional increase in the amount of sand being transported to the depositional site.