Extinct mammalian megafauna 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).
Text material © 2025 by Steven M. Carr