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Dasypus neogaeus; Temporal range: Late Miocene (Huayquerian); ~9–6.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Cingulata
Family:	Dasypodidae
Genus:	Dasypus
Species:	†D. neogaeus
Binomial name
	†Dasypus neogaeus; Ameghino, 1891

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]

History and classification

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]

Description

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]

Paleobiology

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]

Paleoenvironment

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]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Scillato, G. J. (2013). Los Cingulata (Mammalia, Xenarthra) del “Conglomerado Osífero”(Mioceno tardío) de la Formación Ituzaingó de Entre Ríos, Argentina. Publicación Electrónica de la Asociación Paleontológica Argentina, 14(1).
^ ^a ^b ^c ^d Ameghino, F. (1891). Caracteres diagnósticos de cincuenta especies nuevas de mamíferos fósiles argentinos. Revista Argentina de Historia Natural, 1(3), 129–167.
^ Cordeiro de Castro, M. (2015). Sistemática y evolución de los armadillos Dasypodini (Xenarthra, Cingulata, Dasypodidae). Revista del Museo de La Plata| Sección Paleontología, 15.
^ ^a ^b Ercoli, Marcos D.; Álvarez, Alicia; Santamans, Carla; González Patagua, Sonia A.; Villalba Ulberich, Juan Pablo; Constantini, Ornela E. (2019-08-01). "Los Alisos, a new fossiliferous locality for Guanaco Formation (late Miocene) in Jujuy (Argentina), and a first approach of its paleoecological and biochronology implications". Journal of South American Earth Sciences. 93: 203–213. Bibcode:2019JSAES..93..203E. doi:10.1016/j.jsames.2019.04.024. hdl:11336/121466. ISSN 0895-9811. S2CID 155281728.
^ Oliveira, E. V., & Pereira, J. C. (2009). Intertropical cingulates (Mammalia, Xenarthra) from the Quaternary of Southern Brazil: Systematics and paleobiogeographical aspects. Revista Brasileira de Paleontologia, 12(3), 167–178.
^ Abba, A. M.; Zufiaurre, E.; Codesido, M.; Bilenca, D. N. (2015-02-01). "Burrowing activity by armadillos in agroecosystems of central Argentina: Biogeography, land use, and rainfall effects". Agriculture, Ecosystems & Environment. 200: 54–61. Bibcode:2015AgEE..200...54A. doi:10.1016/j.agee.2014.11.001. ISSN 0167-8809.
^ Cione, A. L., Dahdul, W. M., Lundberg, J. G., & Machado-Allison, A. (2009). Megapiranha paranensis, a new genus and species of Serrasalmidae (Characiformes, Teleostei) from the upper Miocene of Argentina. Journal of Vertebrate Paleontology, 29(2), 350–358.
^ Schmidt, G. I. (2013). Los ungulados nativos (Litopterna y Notoungulata: Mammalia) del “Mesopotamiense”(Mioceno Tardío) de Entre Ríos, Argentina. Publicación Electrónica de la Asociación Paleontológica Argentina, 14(1).
^ Schmidt, G. I. (2013). Litopterna y Notoungulata (Mammalia) de la Formación Ituzaingó (Mioceno tardío-Plioceno) de la Provincia de Entre Ríos: sistemática, bioestratigrafía y paleobiogeografía (Doctoral dissertation, Universidad Nacional de La Plata).
^ Góis, Flávio; Scillato-Yané, Gustavo Juan; Carlini, Alfredo Armando; Guilherme, Edson (2013-06-01). "A new species of Scirrotherium Edmund & Theodor, 1997 (Xenarthra, Cingulata, Pampatheriidae) from the late Miocene of South America". Alcheringa: An Australasian Journal of Palaeontology. 37 (2): 177–188. Bibcode:2013Alch...37..177G. doi:10.1080/03115518.2013.733510. hdl:11336/18791. ISSN 0311-5518. S2CID 129039539.
^ Alvarenga, Herculano M. F.; Höfling, Elizabeth (2003). "Systematic revision of the Phorusrhacidae (Aves: Ralliformes)". Papéis Avulsos de Zoologia. 43 (4): 55–91. doi:10.1590/S0031-10492003000400001. ISSN 0031-1049.
^ Babot, J. M., & Ortiz, P. E. (2009). Primer registro de Borhyaenoidea (Mammalia, Metatheria, Sparassodonta) en la provincia de Tucumán (Formación India Muerta, Grupo Choromoro; Mioceno tardío). Acta Geológica Lilloana, 34–48.
^ Riff, D., Romano, P. S. R., Oliveira, G. R., & Aguilera, O. A. (2010). Neogene crocodile and turtle fauna in northern South America. Amazonia. Landscapes and Species Evolution: A Look Into the Past, 259–280.
^ Franco, M. J., & Brea, M. (2015). First extra-Patagonian record of Podocarpaceae fossil wood in the Upper Cenozoic (Ituzaingó Formation) of Argentina. New Zealand Journal of Botany, 53(2), 103–116.