EucholoeopsAmeghino, 1887 (Xenarthra, Tardigrada, Megalonychidae) from the Santa Cruz Formation, Argentine Patagonia: implications for the systematics of Santacrucian sloths

摘要: ABSTRACT New well-preserved remains of the megalonychid sloth Eucholoeops Ameghino, 1887 recovered under strict stratigraphic control from late Early Miocene Santa Cruz Formation (c. 19 to 14 Ma; Santacrucian Age), together with analysis older collections, consideration intraspecific variation in extinct and extant sloths, assessment validity early literature on permit revision status numerous species erected for this genus. The current contribution deals systematics E. ingens 1887, but its methodology provides a basis other species, as well genera Formation. failure make progress taxa since their first description is shown be due mainly combination poor quality many specimens, which are often fragmented incomplete inadequate an...