New remains of the enormous hoplophorine glyptodont Uruguayurus Mones, 1987 (Mammalia, Cingulata) in a particular faunistic association, Raigón Formation (Pliocene–middle Pleistocene), Uruguay

Abstract

A new specimen of the poorly known glyptodont Uruguayurus Mones, 1987, is described on the basis of a large portion of the caudal tube from Arazatí Harbor, San José Department, Uruguay. This fossil is attributed to the Raigón Formation (Pliocene–middle Pleistocene), which crops out in the coastal cliffs of the referenced locality. This unit shows a particular faunal association characterized by endemic species, other representatives of the South American Cenozoic and others of North American origin. The material described herein shows diagnostic characteristics that allow to consider it an hoplophorine glyptodont, pertaining to the genus referred to above, similar to and the probable descendant from the smaller Pseudoplohophorus Castellanos, 1926, which is abundant in deposits of the underlying Camacho Formation (late Miocene) at the same locality. On the basis of this finding, the knownledge of Uruguayurus is increased and its diagnosis expanded. The new specimen has a larger, flatter, and more symmetrical caudal tube than the specimens previously described, named U. authochthonus Mones1987, and U. lydekkeri (Mones, 1987). It is also distinguished from those morphotypes by having an interapical groove of intermedial width, very large apical and first lateral figures, and more abundant and clearly delimited peripheral figurines on the dorsal surface. For now, these differences could be attributed to intraspecific variations within Uruguayurus authochthonus.