> Among the many extinct species that lived in this region are members of the family Megalonychidae (including the genus Megalonyx, Greek for “large claw”). Fossils of these giant ground sloths are commonly found in the caves, as they probably took refuge within them, such as members of the genus Xibalbaonyx (“great claw of Xibalba”), a polar bear-sized ground sloth with big claws that measured up to 12 feet in height and weighed nearly a ton. They are joined by members of related families, including the genus Nothrotheriops, a grizzly bear-sized mammal that reached five feet tall and weighed 1,000 pounds.

It's unfortunate DNA doesn't preserve well in humid environments. Those many bones could provide a lot of genetic information otherwise.