1.7km ENE of Santiago Yolomécatl (Eocene of Mexico)

Also known as Inyoo; Iniyoo

Where: Oaxaca, Mexico (17.5° N, 97.2° W: paleocoordinates 18.9° N, 89.7° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Yolomécatl Formation, Bartonian (41.3 - 38.0 Ma)

• It is ~55 m above the 40Ar/39Ar-dated tuff sheet (40.3 ± 1.0 Ma). Originally thought to be middle or late Eocene and described as the Yolomécatl Formation (Ferrusquia-Villafranca et al. 2018), a new U-Pb zircon maximum depositional age of 30.6 ± 0.77 Ma for a sandstone bed that is within the fossiliferous beds indicates an Arikareean 1 North American Land Mammal Age (NALMA) and it has been assigned to the Chilapa Formation instead (Guerrero-Arenas et al., 2020; see Ortiz-Caballero et al. 2020). However, Ferrusquía-Villafranca and Wang (2021) have argued that it is the Yolomécatl Formation, providing a 40Ar-39Ar age of 40.3 ± 1.0 Ma (latest Uintan-earliest Duchesnean NALMA)

• bed-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; lithology not reported

Size class: macrofossils

Primary reference: I. Ferrusquia-Villafranca, L. J. Flynn, J. E. Ruiz-Gonzalez, J. R. Torres-Hernandez, and E. Martinez-Hernandez. 2018. New Eocene rodents from Northwestern Oaxaca, Southeastern Mexico, and their paleobiological significance. Journal of Vertebrate Paleontology e1514615 [P. Mannion/P. Mannion]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 197503: authorized by Philip Mannion, entered by Philip Mannion on 14.11.2018

Creative Commons license: CC BY (attribution)

Taxonomic list

 Rodentia - Sciuridae
Douglassciurus oaxacaensis n. sp. Ferrusquia-Villafranca et al. 2018 squirrel
IGM-4911 - type