''Asterostemma'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

glyptodont Glyptodonts are an extinct subfamily of large, heavily armoured armadillos. They arose in South America around 48 million years ago and spread to southern North America after the continents became connected several million years ago. The best-k ...

. It lived during the Middle

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

, and its fossilized remains were discovered in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

Description

Like all its close relatives, ''Asterostemma'' had a carapace made of fused

osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct ...

, protecting most of its body. The ornamentation of its osteoderms was similar to other basal genera of glyptodonts, such as '' Propalaehoplophorus'', with clear and shallow furrows, and the central figures were rounded. Those were surrounded by a single row of peripheral figures. The caudal cuirass of ''Asterostemma'' was formed by rings and a caudal tube, forming a long and thin structure, similar to those of modern

armadillo Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, al ...

Classification

''Asterostemma depressa'' was first described by

Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especiall ...

in 1889, based on fossil remains found in Middle

terrains of

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

. Other species attributed to this genus, such as ''A. acostae'', ''A. gigantea'', and ''A. venezolensis'' ; subsequent revisions of the fossil remains determined that the latter species belonged to a distinct genus of glyptodont, ''

Boreostemma ''Boreostemma'' is an extinct genus of glyptodonts from northern South America. Fossils assigned to the genus were first described as belonging to '' Asterostemma'' from southern South America, but have been placed in the new genus ''Boreostemma' ...

''.

Bibliography

*F. Ameghino. 1889. Contribución al conocimiento de los mamíferos fósiles de la República Argentina ontribution to the knowledge of the fossil mammals of the Argentine Republic Actas de la Academia Nacional de Ciencias de la República Argentina en Córdoba 6:xxxii-1027 *A. A. Carlini, A. E. Zurita, G. J. Scillato-Yane, R. Sanchez, and O. A. Aguilera. 2008. New Glyptodont from the Codore Formation (Pliocene), Falcon State, Venezuela, its relationship with the Asterostemma problem, and the paleobiogeography of the Glyptodontinae. Palaontologische Zeitschrift 82(2):139-152 {{Taxonbar, from=Q5709658 Armadillos Prehistoric placental genera Prehistoric cingulates Miocene xenarthrans Miocene genus first appearances Miocene genus extinctions Miocene mammals of South America Neogene Argentina Fossils of Argentina Fossil taxa described in 1889 Taxa named by Florentino Ameghino