Restos de †Panochthus Burmeister (Xenarthra; Cingulata; Glyptodontidae) registrados en áreas de altura: descripción y comentarios

Panochthus Burmeister is one of the most abundant, diversified and widely distributed xenarthrans of the South American Pleistocene, as well as one of the glyptodontids with higher latitudinal and altitudinal distributions. This contribution analyzes those records assigned to the genus, in decreasing order of elevation: (1) MURB 1906: 4000 masl, Potosi (Bolivia). (2) MUSM 3632:  3800 masl, Desaguadero (Peru). (3) MHNC-13491:  2600 masl, Cochabamba (Bolivia). (4) MNPA-V 006598:  1870 masl, Tarija Valley (Bolivia). (5) MUFYCA 383: 920 masl, Traslasierra Valley (Argentina). We discuss the probable relationship between geographic altitude and body mass of P. intermedius Lydekker specimens. In this species, the individuals that inhabited high areas show significantly lower values of body mass than those fromthe Pampas plains. This relationship has also been recorded in other xenarthrans, as well as in other groups of mammals. These taxa could express an inverse Bergmann's rule pattern. In this sense, a “reduction in the availability of resources” could be the ecological reason to account for the smaller size of the individuals studied. P. hipsilis Zurita, Zamorano, Scillato-Yane, Fidel, Iriondo & Gillette is an endemic species fromthe Bolivian Altiplano; its findings represent thegreatest altitudinal records for Panochthus and possibly for the Glyptodontidae.