38,000 YEAR-OLD SUB-FOSSIL EVIDENCE FOR THE ATLANTIC GRAY WHALE, ESCHRICHTIUS ROBUSTUS, SOUTH ATLANTIC BIGHT, GEORGIA (USA)

38, 000 year-old sub-fossil evidence, including a nearly complete dentary (left mandible) and two vertebrae, of the extinct Atlantic Gray Whale, Eschrichtius robustus, have been excavated from a shell bed deposit located in the South Atlantic Bight, 30 kilometers offshore St. Catherine’s Island, Georgia. The discovery of the dentary was initially made in 2006 but recovery was not completed until the summer of 2008. The two vertebrae were found nearby the jaw section and had been eroded from the shell bed by bottom currents. Direct dating of the sub-fossils, with the Accelerator Mass Spectometer radiocarbon technique (AMS), using bioapatite, suggests a common age for the skeletal materials but it speculative to assume these are elements of the same animal. The ages determined for the sub-fossils are in good agreement with the age of the shell bed previously determined by AMS dating of inclusions and by direct dating of the sediments using Optical Stimulated Luminescence (OSL) dating. Surviving architectural features of the mandible provide convincing evidence that the discovery is that of a Pleistocene aged member of the monospecific Eschrichtiae clade. As such it is the oldest known evidence of this extinct taxon in the Atlantic Basin.