Glyptodon. Illustration and photo-reconstruction of the prehistoric armadillo Glyptodon. Glyptodonts were large, more heavily armoured relatives of extinct pampatheres and modern armadillos. They first evolved during the Miocene in South America, which remained their centre of species diversity. The main feature of glyptodonts was their tortoise-like body armour (osteoderms). Each species of glyptodont had a unique osteoderm pattern and shell type. Glyptodonts also had size on their side; many such as the type genus, Glyptodon, were the size of modern automobiles. Glyptodonts became extinct at the end of the last ice age along with a large number of other megafauna species. Their much smaller, more lightly armoured and flexible relatives, the armadillos, survived.