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 3.9 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).
History and phylogeny In the 1870s, fossils attributable to Glyptotherium were found by civil engineers Juan N. Cuatáparo and Santiago Ramírez collected a glyptodont specimen from a drainage canal near Tequixquiac, Mexico. The fossils came from the Rancholabrean age, which corresponds to the Pleistocene epoch of the Quaternary Period. This specimen, a skull, nearly complete carapace (top shell), and associated postcranial skeleton, was the first discovery of a glyptodont in North America. Cuatáparo and Ramírez named the fossils Glyptodon mexicanum in 1875, but the fossils have been lost. Another species of Glyptodon from Mexico was described in 1889, G. nathoristi, by German paleontologists based on carapace remains from Pleistocene localities in Ejutla, Oaxaca. In 1888, paleontologist Edward Drinker Cope described a single carapace osteoderm that had been collected from the Lower Pleistocene "Equus Beds" of Nueces County, Texas. Cope named this osteoderm Glyptodon peltaliferus, but he did not give the species a proper description that followed ICZN rules, making it a nomen nudum and a synonym of G. cylindricum. The next year, Joseph Leidy named Glyptodon floridanus based on isolated carapace osteoderms and pieces of caudal armor, which he initially referred to G. peltaliferus, that were collected from Pleistocene deposits in DeSoto County, Florida. This species is a nomen vanum (invalid name) and considered a synonym of Glyptotherium cylindricum according to a review of the genus by American paleontologists David Gillette and Clayton Ray (1981).
… excerpt ends here. Continue reading the full article.
