Dasypus neogaeus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Cingulata |
Family: | Dasypodidae |
Genus: | Dasypus |
Species: | †D. neogaeus
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Binomial name | |
†Dasypus neogaeus Ameghino, 1891
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Dasypus neogaeus is an extinct species of armadillo, belonging to the genus Dasypus, alongside the modern nine-banded armadillo. The only known fossil is a single osteoderm, though it has been lost, that was found in the Late Miocene strata of Argentina.[1]
Fossils of Dasypus neogaeus were first collected from the Late Miocene “Osiferous Conglomerate” of the Ituzaingo Formation of Parana, Entre Rios Province in northern Argentina by paleontologist Florentino Ameghino.[1][2] However, some authors recently have stated that the fossils may have come from the Pleistocene.[3] The fossils consisted only of a single, mobile osteoderm from the dorsal carapace.[1][2] The osteoderm was then sent to the Bernardino Rivadavia Natural Sciences Argentine Museum in Buenos Aires, where it was described and named Dasypus neogaeus by Ameghino in 1891.[2][1] Since then, no additional fossils have been assigned to the taxon, although fossils of the same age have been unearthed in other areas of Argentina.[4][5]
The holotype osteoderm measures only around 13 millimeters long, but indicates a species larger than Dasypus hybridus but smaller than D. novemcinctus.[1] The osteoderm also differs from that of other species in that it bears more piliferous foramina, 8 in total, on the posterior end than D. novemcinctus.[2][1][4] Although it only bears 2 physical diagnostic features and is known from very fragmentary fossils, more diagnostic characters could be in the histological anatomy of the osteoderm.[1]
Based on the taphonomic and environmental information provided by the “Osiferous Conglomerate” the holotype was found in, D. neogaeus lived in areas with gallery forests near water.[1] This is contrary to the modern Dasypus species, which live in grasslands, suggesting that Dasypus and other smaller armadillos recently underwent an ecological change.[6][1]
Fossils have only been unearthed from the Ituzaingó Formation of Entre Rios, Argentina, which preserves vast tidal flats similar to those in the modern day Amazon and a warm climate.[7] Large, herbivorous notoungulate mammals in the Ituzaingó Formation were widespread, including the toxodontids Xotodon and Adinotherium,[8] and litopterns such as Brachytherium, Cullinia, Diadiaphorus, Neobrachytherium, Oxyodontherium, Paranauchenia, Promacrauchenia, Proterotherium and Scalabrinitherium.[9] Large, armored glyptodonts like Palaehoplophorus, Eleutherocercus, and Plohophorus[1] lived in the area as well as other cingulates like the pampatheres Kraglievichia[1] and Scirrotherium.[10] Carnivores included the phorusrhacids Devincenzia and Andalgalornis[11] and sparassodonts,[12] with giant crocodilians like Gryposuchus and Mourasuchus in the freshwater.[13] Bamboos, coconut palms, and other palms were prevalent.[14]