Glyptotherium

Glyptotherium Temporal range: Early Pliocene (Zanclean)-Late Pleistocene ~3.6–0.015 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
G. texanum holotype (USNM 10536), National Museum of Natural History
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Cingulata
Family:	Chlamyphoridae
Subfamily:	†Glyptodontinae
Genus:	†Glyptotherium Osborn, 1903
Type species
†Glyptotherium texanum Osborn, 1903
Other Species
† G. cylindricum (Brown, 1912)
Distribution of Glyptotherium (orange) compared to Glyptodon's (green).
Synonyms
Boreostracon Simpson, 1929 Brachyostracon Brown, 1912 Xenoglyptodon Meade, 1953 Synonyms of G. texanum Glyptotherium arizonae Gidley, 1926 Xenoglyptodon fredericensis Meade, 1953 Glyptodon fredericensis (Meade, 1953) Synonyms of G. cylindricum Glyptodon mexicanum Cuatáparo and Ramírez, 1875 Glyptodon nathorsti Felix and Lenk, 1875 Glyptodon petaliferus Cope, 1888 Brachyostracon cylindricum Brown, 1912 Brachyostracon mexicanum (Cuatáparo and Ramírez, 1875) Glyptodon rivipacis Hay, 1923 Boreostracon floridanus Simpson, 1929 Glyptotherium floridanum Simpson, 1929 Glyptotherium mexicanum (Cuatáparo and Ramírez, 1875)

Glyptotherium (from Ancient Greek for 'grooved or carved beast') is a genus of glyptodont (an extinct group of large, herbivorous armadillos) in the family Chlamyphoridae that lived from the Early Pliocene, about 3.6 million years ago, to the Late Pleistocene, around 15,000 years ago. It was widely distributed, living in the United States, Mexico, Guatemala, Costa Rica, Honduras, El Salvador, Panama, Venezuela, Colombia, and Brazil. Fossils that had been found in the Pliocene Blancan Beds in Llano Estacado, Texas were named Glyptotherium texanum by American paleontologist Henry Fairfield Osborn in 1903. Another species, G. cylindricum, was named in 1912 by fossil hunter Barnum Brown on the basis of a partial skeleton that had been unearthed from the Pleistocene deposits in Jalisco, Mexico. The two species differ in several aspects, including age: G. texanum is from the older Early Pliocene to Early Pleistocene strata, whereas G. cylindricum is exclusive to the Late Pleistocene.

Glyptotherium was a large, four-legged (quadrupedal), herbivorous armadillo with an armored top shell (carapace) that was made of hundreds of interconnected osteoderms (structures in dermis composed of bone). Other pieces of armor covered the tail and cranium roof, while small pebbly pieces of armor were in the skin. Glyptotherium grew up to 2 meters (6.56 feet) in length and 400 kilograms (880 pounds), making it one of the largest glyptodonts known. Glyptotherium is morphologically most similar to Glyptodon: though they differ in several ways. Glyptotherium is smaller on average, with a shorter carapace, a longer tail, and had a different distribution.

Glyptodont diversity diminished into the Pleistocene, though they peaked in size during this period. Glyptotherium is considered an example of American megafauna, most of which are now extinct, and may have been wiped out by changing climate or human hunting. Glyptotherium was primarily a grazer that lived on open grasslands, though it also consumed fruits and other plants. The armor could protect the animal from predators, including the "saber-tooth cat" Smilodon, the "bone-crushing dog" Borophagus, and the "short-faced bears" (Tremarctinae).