Where: Argentina (49.5° S, 68.4° W: paleocoordinates 50.4° S, 61.2° W)

• coordinate estimated from map

When: Monte Leon Formation, Aquitanian (23.0 - 20.4 Ma)

• Age after Parras et al 2008

•

•Parras et al., 2008: No isotopic data are available on the lower part of the Monte León Formation, and the only radiometric 40Ar/39Ar age of 19.33 Ma is from the top of the unit (Fleagle et al., 1995). The 87Sr/86Sr age of 23.83 and 24.12 Ma (latest Oligocene) drawn from top of the San Julián Formation immediately be- low its contact with the overlying Monte León Formation at Cabo Curioso, suggest that the age of the latter at the localities along the coast should lie between 24.12 and 19.33 Ma, i.e., latest Oligo- cene or more probably early Miocene (see Fig. 8).

• formation-level stratigraphic resolution

Environment/lithology: marginal marine; tuffaceous, gray siltstone and tuffaceous, gray sandstone

Size class: macrofossils

Preservation: original phosphate

Primary reference: A. L. Cione and M. A. Cozzuol. 1990. Reidentification of Portheus patagonicus Ameghino, 1901, a supposed fish from the Middle Tertiary of Patagonia as a delphinoid cetacean. Journal of Paleontology 64(3):451-453 [M. Uhen/M. Uhen/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 45887: authorized by Mark Uhen, entered by Mark Uhen on 12.12.2004

Creative Commons license: CC BY (attribution)