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Xenarthra Pilosa del Neógeno del Ecuador: sistemática, distribución estratigráfica, paleobiogeografía y paleoambientes

Abstract:

The prolonged isolation of the South American subcontinent for almost 100 million years allowed the development of its own mammalian fauna that was affected some 3 million years ago by the north-south and south-north migratory movements that occurred as a result of the closure of the Isthmus of Panama, a process known as the Great American Biotic Exchange (GABI). Among this characteristic fauna are the superorder of placental mammals of the Xenarthra (anteaters, armadillos and sloths), characterized by anatomical peculiarities exclusive to the group. Sloths are grouped in the Folivora suborder, belonging to the Pilosa order, which includes the arboreal sloths, with both extant and fossil representatives, and the ground sloths, exclusively fossil. The rich record of ground sloths in South America shows the diversity reached by the group illustrated by the wide range of sizes, types of diets and locomotion. Its evolution and distribution patterns were conditioned by the orography, climate and migration events which are not yet fully clarified. This Doctoral Thesis addresses the review of the material of fossil sloths from Ecuador, increasing the existing data with new material collected in 6 locations from the Miocene and Pleistocene, thereby contributing to increase the record of this fossil fauna providing new data that serves to clarify the evolutionary history of the Xenarthra-Pilosa.