ZURITA Alfredo Eduardo
congresos y reuniones científicas
First record of Neuryurus Ameghino, 1889 (Xenarthra, Glyptodontidae) in Chuí creek and a comparison between Glyptodontid faunas from Southern Brazil and the Mesopotamian region of Argentina
San Juan
Congreso; VI Congreso Latinoamericano de Paleontología de Vertebrados; 2011
Institución organizadora:
The Chuí Creek exposed near the ridge between Santa Vitória do Palmar City and Hermenegildo Beach (33°35’26,39’’S and 53°20’22,11’’W) contains one of the best records of late Pleistocene (Lujanian Age/Stage) mammals found in Brazil.The deposits along this creek show beach facies at the base, characterized by middle grained sandstone, overlapped by a thick layer of muddy sandstone, probably fluvial or lagoonal in its origin, where there are the mammal fossils. Here is reported the first record of Neuryurus Ameghino 1889 from this locality, represented by an isolated osteoderm. The specimen was found among dredged sediments; it is dark-colored and well-preserved, complete and without signs of abrasion. The exposed surface is rugose and bears pilose foramina, which is typical of the genus. Besides Neuryurus, other glyptodontids found in Chuí Creek include Glyptodon Owen 1839, Panochthus Burmeister 1866 and Doedicurus Burmeister 1874. All specimens are represented by isolated osteoderms and partial carapaces; the most abundant genus is Glyptodon, followed by Panochthus, while Doedicurus is very scarce and Neosclerocalyptus Paula Couto 1957 absent. This palaeofaunal association and its frequency of records are quite similar to that observed in the late Pleistocene of the Mesopotamian region, and different from the Pampean region, where Neosclerocalyptus is one of the most frequent glyptodont. In this sense, it is interesting to remark that Neosclerocalyptus (very frequent in the Pampean region but very scarce in the Mesopotamian region and absent in southern Brazil) is one of the most clearly Pleistocene genus adapted to cold and arid/semiarid environments. In turn, Glyptodon seems to have an important ecological tolerance since it is very frequent in the three mentioned regions and it appear associated to both pampean and intertropical taxa. The close resemblance between the southern Brazil and the Mesopotamian region certainly shows a similar palaeoclimatic pattern during, at least, late Pleistocene and corroborates the proposal of a close paleobiogeographic relation between southern Brazil, Argentine Mesopotamia and northern Uruguay.