New cervids (Artiodactyla, Mammalia) from the Yumidong Cave Site in Wushan County, Chongqing
The Yumidong is a Paleolithic cave site discovered in Miaoyu Basin of Wushan County, Chongqing Municipality, Southwest China. The background, lithostratigraphic section and dating results of this site have been described, and the comprehensive analysis of dating results and faunal comparison shows an age of late Middle to Late Pleistocene for the site, about 300 ka to 14 ka, corresponding to MIS 8~2. Many cervid fossils have been unearthed from this site, which provide pretty good materials for the morphological comparisons of Cervidae in the Middle to Late Pleistocene of South China. Three genera and species have been recognized, including Muntiacus muntjak margae, Rusa unicolor and Cervus (Sika) grayi. M. m. margae is only found from the late Middle Pleistocene deposit in the Yumidong Site, having similar size with M. gigas but shorter main beam and longer brow tine than the latter. R. unicolor is larger than C. (S.) grayi, and its antler is robust with well developed longitudinal grooves and crests on the surface. The bifurcation angle between brow tine and main beam is acute. C. (S.) grayi is somewhat slender, and the surface of its antler is ornamented with shallow longitudinal grooves. The bifurcation angle between brow tine and main beam is obtuse. M. m. margae and R. unicolor are both the most common taxa in the Middle to Late Pleistocene mammalian fauna of South China, but C. (S.) grayi is known as a typical Middle Pleistocene species of North China, even it was also found from some Late Pleistocene localities in East China and Japanese archipelago. In term of stratigraphic distributions, specimens of R. unicolor were unearthed from most layers of the deposit in the Yumidong Site, but C. (S.) grayi was only found from limited layers that can be corresponded to MIS 2, MIS 6 and MIS 8. The presence of C. (S.) grayi indicates paleoenvironmental fluctuation during the late Middle to Late Pleistocene in the Three Gorges area.