Gondwanatheria is an extinct group of mammaliaforms that lived in the Southern Hemisphere, including Antarctica, during the Upper Cretaceous through the Miocene (and possibly much earlier, if is a member of this group). Until recently, they were known only from isolated teeth, a few lower jaws, two partial skulls and one complete cranium. Because of this fragmentary knowledge, their placement is not clear, although more details have emerged from newer finds and studies.