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Glyptodon Fossil range: Pleistocene
Fossil specimen in Washington, DC at the National Museum of Natural History
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Superorder: Xenarthra Order: Cingulata Family: Glyptodontidae Genus: Glyptodon Owen, 1839

Glyptodon (Greek for "grooved or carved tooth") was a large, armored mammal, related to the armadillo, that lived during the Pleistocene Epoch. Flatter than a Volkswagen Beetle, but about the same general size and weight, the Glyptodon is believed to have been a herbivore, grazing on grasses and other plants found near rivers and small bodies of water. A large and heavy mammal, it could probably only have moved one or two miles per hour.

Its physical appearance superficially resembled the much earlier dinosaurian ankylosaurs, an example of the convergent evolution of unrelated lineages into similar forms.

Evolutionary history

Glyptodon are part of the placental group of mammals known as Xenarthra. This order of mammals includes anteaters, tree sloths, extinct ground sloths, and armadillos.

Glyptodon originated in South America and first appeared in the American Southwest after North and South America connected at the Isthmus of Panama, about 2.5 million years ago. They became extinct about 10,000 years ago. The native human population in their range is believed to have hunted them and used the shells of dead animals as shelters in inclement weather.^[1][2]

Anatomy

Glyptodon were covered by a protective shell composed of more than 1,000 one inch-thick bony plates, called osteoderms or scutes. Each species of glyptodont had its own unique osteoderm pattern and shell type. With this protection they were armored like turtles, but unlike most turtles, could not withdraw their heads, so they developed a bony cap on the top of their skull. Even the tail of Glyptodon had a ring of bones for protection. Such a massive shell needed considerable support, evidenced by features such as fused vertebrae, short but massive limbs, and a broad shoulder girdle.(Lambert, 196)

The nasal passage was reduced with heavy muscle attachments for some unknown purpose. Some have speculated that the muscle attachments were for a proboscis, or trunk, much like that of a tapir or elephant. Most animals with a trunk, however, have nasal bones receding back on the skull, and glyptodons do not have this feature. The lower jaws were very deep and helped support massive chewing muscles to help chew the coarse fibrous plants that can be found along river and lake banks.

Glyptodon skull

Glyptodon foot

Predators of the Glyptodon could have included the sabre-toothed cat, although this predator would likely have struggled to turn the 1 to 2-ton animal over to reach its unprotected belly.

See also

• Glyptotherium texanum

Notes

References

• David Lambert and the Diagram Group. The Field Guide to Prehistoric Life. New York: Facts on File Publications, 1985. ISBN 0-8160-1125-7

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Glyptodon

Gallery

Glyptodon asper

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