ENVIRONMENTAL CONTEXT OF EXTINCT SLOTH REMAINS AT AN UNDERWATER CAVE IN WESTERN CUBA (Invited Presentation)

Recent multi-disciplinary investigations at a subaquatic cave in western Cuba, named Cueva Chicharrones, have revealed the bone remains of at least three rare, extinct sloths. The bones include an individual of the species Megalocnus rodens and two individuals of the species Neocnus gliriformis. These animals were endemic to Cuba and are believed to have gone extinct 4000 years ago – although only a handful of radiocarbon-dated extinct sloth remains exist for the Caribbean. A network of sediment cores were collected from Cueva Chicharrones to study the water level history of the cave, the environmental context of the paleontological materials, and landscape change outside the cave during the late Quaternary. The sediment cores nearest the cave entrance consist largely of sand-sized calcite particles along with organic matter, in addition to large quantities of seeds from Cecropia and Ficus trees. We hypothesize that the main mechanism by which the seeds entered the cave is through droppings from frugivorous bats, and their presence is likely indicative of times of low water level which provided access to the open cave. Farther in the cave, sediments more closely associated with the sloth remains are rust-coloured, fine textured, and silicate-rich, and were probably deposited in the cave by running water when the cave was a vadose environment. These sediments have been radiocarbon dated to the late Pleistocene/early Holocene and underlie the sloth remains, suggesting that the sloths postdate the deposition of this material. The silicate-rich nature of these sediments is also unusual for a limestone-dominated region, and we tentatively hypothesize that this material represents “African dust” transported across the Atlantic. In summary, there is little information on the specific environments in which now-extinct mammals in the Caribbean lived, and this study illustrates how sediments from underwater caves can be used to provide context for paleontological research.