A PRESERVED THORACIC VERTEBRA OF A PALAEOPHIS SNAKE REPRESENTS THE EARLIEST OCCURRENCE OF SEA SNAKES IN SOUTH CAROLINA

Palaeophiidae is an extinct family of large sea snakes, with a Tethyan to North Atlantic distribution, existing from the Late Cretaceous to the Late Eocene. Previous research has identified Palaeophiids in marine strata in Europe, India, Myanmar, and the Southeastern United States. They have commonly been identified by a single, or a small number of, preserved thoracic vertebrae. No skulls have been recovered, but vertebral morphology suggests that the taxon may be closely related to Boidae, thus representing a separate (and therefore convergent) marine adaptation from modern sea snakes (Elapidae). We report the first specimen of a palaeophiid from South Carolina, currently held in the collection of the Mace Brown Museum of Natural History in Charleston, SC (Specimen #: CCNHM 2901). The specimen is a single preserved thoracic vertebra recovered from the Harleyville Formation of South Carolina. The position of the vertebra along the body has not yet been determined. Preliminary investigation suggests that the specimen most likely belongs to Palaeophis or Pterosphenus. This initial classification is due to similarities in vertebral morphology to previously described members of the genera. The vertebra shows evidence of developed pteropophyses and hypapophyses that may be diagnostic of palaeophiids. However, the full length of these processes have not been preserved. Additionally, the specimen shows a rounded, but longitudinally compressed, centrum that suggests palaeophiid origin. The Harleyville Formation was deposited in the Late Eocene (Priabonian stage), which is consistent with the end of the geologic range of Palaeophiidae.