Barranca alta de la margen Sur del arroyo La Ensenada (Pliocene of Argentina)

Where: Entre Rios, Argentina (32.0° S, 60.6° W: paleocoordinates 32.1° S, 59.8° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Alvear Formation (Punta Gorda Group), Late/Upper Pliocene (3.6 - 2.6 Ma)

• basal levels of the Punta Gorda Group, preliminary correlated with the Fm. Alvear (Iriondo 1980 and Brunetto et al., 2007) and tentatively referrable to the late Pliocene (Marplatan?)

•The Alvear Formation appears almost continuously along the Paraná Canyon, from the entrance of the Nogoyá stream in the Delta to the town of La Paz, 300 km to the N., (Iriondo, 1980). It lies discordantly on the Paraná Formation, only in those locations where the Ituzaingó Formation is absent, with a maximum thickness of 9 m.

•The age of the Alvear Formation, traditionally attributed to the lower Pleistocene (Ensenadense; Iriondo, 1998), is being reviewed based on the findings of hegetothermal caviomorphic and notoungulated rodents at levels of the Punta Gorda Group correlated with the first geological unit and outcrops in the near the city of Diamante (Candela et al., 2007). The ungulates were represented so far by the Pachyrukhinae Paedotherium cf. typicum

•Geological correlation studies currently under way, as well as future new findings

•Fossil materials will allow us to adjust the information on their stratigraphic origin and the geological age of the carrier sediments.

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• formation-level stratigraphic resolution

Environment/lithology: terrestrial; concretionary, nodular, brown, green, calcareous claystone

• limestone concretions formed by nodules and horizontal and vertical plates of whitish calcium carbonate. Among the plates, there is a powdery, non-chalky powdery clay slime of pinkish brown and greenish brown with thin nodules and layers of manganese.

•Towards the roof, the Hernandarias, La Juanita, Punta Gorda formations can be superimposed, or, in those places where they are missing, fine brown clay silt with calcium carbonate nodules from the Pinto Tezanos formation.

Size class: macrofossils

Primary reference: G. I. Schmidt, M. A. Reguero, and J. I. Noriega. 2008. Notoungulata y Litopterna en el Plioceno de Entre Ríos, Argentina. In J. Calvo, J. Porfiri, B. Gonzalez Riga, D. Dos Santos (eds.), Paleontologia y dinosaurios desde America Latina 223-234 [P. Mannion/M. Kouvari]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 207682: authorized by Philip Mannion, entered by Miranta Kouvari on 27.01.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Notoungulata - Toxodontidae
Toxodontidae indet. Scott 1873 notoungulate
CICYTTP-PV-M-1-281 to 283
 Notoungulata - Hegetotheriidae
Paedotherium cf. typicum Ameghino 1887 notoungulate
CICYTTP-PV-M-1-280
 Panameriungulata - Proterotheriidae
Proterotheriinae indet. Ameghino 1885 placental
CICYTTP-PV-M-1-284