Glyptodon clavipes (Osborn 1903, 2m, 4-.012mya) was once widely regarded as a giant armadillo (Dasypus), but here nests as an armored sloth. Note the similarities in the skull.

The cervicals are fewer, the dorsal and sacral vertebrae are fused into one bone along with the pelvis and the tail has deep chevrons. The phalanges are reduced to disks supporting robust claws. Several bony processes support the the bony shell from the inside. Like sloths, and unlike armadillos, this was a slow-moving mammal.