Extinct mammals from South America

Extinct mammalian megafaunal from South America, as observed by Darwin

Remains of large, extinct mammals from South America were already known to European biologists, but it made a difference when Darwin saw them for himself. The Giant Ground Sloth (Megatherium) [left] stands 7 1/2 ft tall, and is related to modern tree sloths and armadillos in the superorder Xenarthra. Darwin's skull of Mylodon is similar. Glyptodon [next right] is 11 ft long and has a 'shell' of more than 1,000 osteoderms, like those of modern armadillos in the same superorder. Toxodon [lower left] is 9 ft long and was the last surviving member of the extinct order Notungulata: like modern ungulates is has a characteristic diastema (gap) between the forward spade-like incisors and the molariform hind teeth. Macrauchenia [bottom right] is a three-toed member of the extinct order Litopterna, and a relative of modern odd-toed Perissodactyla (horses & rhinos).