AN UNKNOWN UNGULATE: IDENTIFYING A LATE PLEISTOCENE MAMMOTH CO-HABITANT AT THE MAMMOTH SITE OF HOT SPRINGS, SOUTH DAKOTA

The Mammoth Site documents a Late Pleistocene (26-27 Kya) megafauna in the southern Black Hills of South Dakota. This site is interpreted as a sinkhole resulting from a karstic landscape that became a behaviorally selective trap for adolescent to adult male mammoths (Mammuthus columbi and M. primigenius). Several other large mammalian taxa have been collected from this locality, including: Camelops hesternus, Hemiauchenia macrocephala, Euceratherium collinum, Arctodus simus, and Canis lupus. However, the fauna recovered from the site is depauparate in regards to characteristic Rancholabrean taxa. Large predators are typically uncommon, so absence of these taxa in not unexpected. Large herbivores are far more common, particularly those that herd, such as Equus and Bison. However, these taxa are conspicuously absent at the Mammoth Site. Recently, perusal of collections noted the presence of a disarticulated proximal femoral epiphysis. The speci men, originally found on site in 1976, is far too small to be Mammuthus yet large enough to identified as megafauna. Visual assessment of the epiphysis has ruled out camelid, equid, ursid, and felid taxa and suggests bovid affinities, resembling Bison sp., most likely B. antiquus. The specimen is currently being compared through morphometric analyses to large artiodactyls, including a wide variety of bovids and cervids.