Confusion with Megatherium (1769–1832), describer of
Megatherium|alt=Portrait of Georges Cuvier, describer of Megatherium. The history and taxonomy of
Glyptodon is storied and convoluted, as it involved confusion with other genera and
dubious species, as well as a lack of detailed data. The first recorded discovery of
Glyptodon was as early as 1814 when Uruguayan priest, scientist, soldier, and later politician
Dámaso Antonio Larrañaga (1771–1848) wrote about the discovery of several unusual fossils in his
Diario de Historia Natural, which included his descriptions of many new species of ants, birds, mammals, and even one of the first figures of the extinct
Megatherium, a genus of giant
ground sloth that was named in 1796 by French scientist
Georges Cuvier (1769–1832). This was the first recorded discovery of a
glyptodontine or fossil
cingulate. Larrañaga identified the fossils as those of
Dasypus (
Megatherium), believing that
Megatherium was a subgenus of
Dasypus based on the incorrect referral of glyptodontine osteoderms to
Megatherium years earlier by Spanish scientist Juan Bautista Bru de Ramón, which misled other scientists to believe that glyptodontine fossils were actually those of armored megatheres. Larrañaga also noted that similar fossils had been found in "analogous strata near
Lake Mirrim, on the frontier of the Portuguese colonies" (
southern Brazil). The femur and caudal armor were recovered from the
Queguay in northern Uruguay, while the carapace had been found in the
Arapey River. The fossils included osteoderms comparable to those described earlier by Larrañaga, as well as teeth, skull fragments, limb bones, and other elements.
Pachypus by Eduard D'Alton in 1839, Saint-Hilaire considered the osteoderms found by Sellow to not even be mammal, but instead of a relative of
Teleosaurus, a crocodile-like reptile known from
Jurassic deposits in France. Parish later collected several more fossils from localities in
Las Averias and
Villanueva; the latter including a partial skeleton containing a mandible fragment and a set of partial limbs. This skeleton was deposited in Parish's collection at the Royal College of Surgeons upon his return to the United Kingdom. Within this book, Owen erroneously believed the fossils from Las Averias and Villanueva were all from the same specimen, which he named
Glyptodon ("grooved tooth") based on the anatomy of the molariform. However, the lectotype of
G. clavipes was undiagnostic and indistinguishable from other
Glyptodon species and even
Glyptotherium, making it dubious. Later in 1845, many more fossils found by Parish from Pleistocene layers in Argentina were named as new species of
Glyptodon by Owen:
G. ornatus,
G. reticulatus,
G. tuberculatus, and
G. clavicaudatus in 1847. Of these additional species, only
G. reticulatus is still considered a valid species of
Glyptodon as
G. ornatus was reassigned to the genus
Neosclerocalyptus, G. tuberculatus to
Panochthus, and
G. clavicaudatus to
Doedicurus.
G. reticulatus was named on the basis of several carapace fragments that had also been recovered from the Matanza River, but they lack detailed locality information and the fossils too were destroyed during WWII. The fragments were cast by the
Natural History Museum (NHMUK) as well, being used to diagnose the species. Other paleontologists also started erecting names for
Glyptodon species after the 1840s, but many of them are now seen as dubious, species inquirenda, or synonymous with previously named species. but it has since been synonymized with
G. reticulatus. Another species now seen as valid,
G. munizi, was described in 1881 by Argentine paleontologist Florentino Ameghino (1853–1911) on the basis of several osteoderms found in the Ensenadan of
Arroyo del Medio,
San Nicolás, Argentina. For many years the taxon was only known from the fragmentary holotype, but skull and complete carapace material of the species was later described in detail in 2006 that cemented its validity.
P. uquiensis has been synonymized with
Glyptodon and is possibly a valid species, though further analysis is necessary to settle its status. but it has since been found to be an indeterminate specimen of
Glyptodon. Another
Glyptodon species was described in 2020 called
G. jatunkhirkhi by several authors led by Argentine zoologist
Francisco Cuadrelli on the basis of an individual preserving a nearly complete carapace, several caudal rings, and a pelvis that had been collected from
Yamparaez, southeast of the Bolivian city of
Sucre. The strata they were found in was made up of fluvial, sandy sediments that dated to the
Late Pleistocene from elevations as high as above sea level. Several additional paratypes were referred to the species from other Late Pleistocene sites in
Eastern Cordillera, Bolivia including a nearly complete skull and several osteoderms. Several other North American glyptodontine species were named throughout the late 19th-early 20th century, typically based on fragmentary osteoderms. All North American and Central American fossils of glyptodontines have since been referred to the closely related genus
Glyptotherium, which was named in 1903 by American paleontologist
Henry Fairfield Osborn. == Taxonomy ==