Cenozoic vertebrate biostratigraphy of South Carolina, U.S.A., and additions to the fauna

Abstract

Study of vertebrate fossils from the South Carolina Coastal Plain played a significant role in the early history of vertebrate paleontology as a scientific discipline in North America. However, a clear understanding of the state’s vertebrate biostratigraphy has been greatly hindered by the paucity of well-exposed fossil-bearing stratigraphic sections and a complicated subsurface stratigraphy. Most units, particularly those of Neogene and Quaternary age, exist as thin veneers of marine or estuarine sediments that typically occur as infilled topographic lows or erosional remnants as determined primarily from borehole stratigraphy. Hence, lateral continuity can be difficult to confirm over broad geographic areas often resulting inconfusion insofar as vertebrate fossil provenance is concerned. The evaluation of vertebrate fossils from the South Carolina Coastal Plain presented here, and of the geologic units from which they originated, or are thought to have originated, results in the first modern biostratigraphic framework for the known Cenozoic record of the state. Results provide (1) updated correlations of many units to the most recent, astronomically-tuned marine oxygen isotope stages; (2) the first viverravid from the Atlantic Coastal Plain, Didymictis proteus; (3) new information on the timing of certain Neotropical immigrants into the Southeast during the Great American Biotic Interchange, including the oldest record of Erethizon in this region and the oldest records of capybara in the USA; (4) the possible oldest record of the microtine rodent Allophaiomys pliocaenicus in the USA; (5) new details on the unit of origin for the type specimen of the archaeocete Dorudon serratus; and (6) new details on the ontogeny of the early odontocete Agorophius pygmaeus. New taxonomic records from South Carolina include Glyptotherium texanum, Holmesina floridanus, Ondatra idahoensis, Erethizon ?bathygnathum, Leopardus amnicola, Miracinonyx ?trumani, Canis lepophagus, Canis latrans, Phocanella pumila, Callophoca obscura, Monatherium sp., Anchippus texanus, Subhyracodon mitis, Aphelops ?malacorhinus, Teleoceras ?guymonense, and Perchoerus sp. New specimens of previously recorded taxa are also noted.