The cingulates (Mammalia: Xenarthra) from the late Quaternary of northern Brazil: Fossil records, paleoclimates and displacements in America

Abstract

This paper presents the Quaternary cingulates collected from two limestone caves in Aurora do Tocantins, northern Brazil. Osteoderms of Euphractus sexcinctus, Dasypus novemcinctus, Propraopus sulcatus, and Pachyarmaterium brasiliense were retrieved, representing an expansion on the known distribution of the taxa. The specimens are described herein, and their geographic and chronologic distributions in Brazil are reviewed. Numerical dates allied to the presence of biostratigraphically relevant taxa indicate a Late Pleistocene–middle Holocene age. Considering that E. sexcinctus and D. novemcinctus occupy the area nowadays, why did part of the past cingulate community survive and the other part became extinct? We believe that their distribution was affected by paleoclimatic shifts, especially during glacial/interglacial cycles. The colder and arid climate of the Pleistocene glacial periods favored the development of open forests and savannas in Brazil, whereas grasslands and steppes were predominant in higher latitudes. Probably, Propraopus and Pachyarmatherium (from south and north, respectively) took refuge in lower latitudes, including in Brazil. Later, during the interglacial cycle, warm and moist climates favored the development of an evergreen forest in central Brazil, leading Propraopus and Pachyarmatherium to extinction and positively selecting E. sexcinctus and D. novemcinctus.