Also known as TAR 20

Where: Peru (6.6° S, 76.3° W)

• Paleocoordinates: 6.6° S, 65.7° W (Wright 2013)

• coordinate stated in text

• small collection-level geographic resolution

When: Deseadan mammal zone, Pozo Shales Member (Pozo Formation), Rupelian to Rupelian (33.9 - 23.0 Ma)

• Campbell et al. (2021). Our BTD results are also inconsistent with the latest Eocene and earliest Oligocene ages that Antoine et al. (2021) have proposed for the Shapaja localities. Though our analyses do not correctly predict the sequence of the Shapaja localities, the mean estimates for individual species nevertheless range from 31.6 to 20.7 Ma, with composite means for the section ranging from 29.1 to 28.3 Ma. The composite mean estimates for the Shapaja section are all very close to those for Santa Rosa, differing by only 0.42 to 1.0 My across analyses with both broad (effectively “unknown”) and more restricted age priors. These results are consistent with the close correlation of the Shapaja and Santa Rosa sections originally proposed by Boivin et al. (2018). Antoine et al. (2021) note that their placement of the Shapaja localities near the Eocene–Oligocene boundary implies that these faunas include 14 new first appearances in South America (either at the genus, family, or superfamily level), with most of the taxa in question otherwise first known from Deseadan (Upper Oligocene) localities. With the geochronological evidence now available from Santa Rosa, and the biochronological evidence for a close correlation of the Shapaja and Santa Rosa sections, we propose that a more parsimonious explanation for the occurrence of otherwise Deseadan taxa in the Shapaja localities is that those localities are, in fact, Deseadan in age. Given such an age estimate, we suggest that the two positive δ13C excursions identified in the Shapaja chemostratigraphies would be better correlated with those that occur at ∼26.5 and ∼25.5 Ma in the generalized global record (ref. 28, their figure 28.11).

• bed-level stratigraphic resolution

Environment/lithology: fluvial-deltaic; conglomerate

Size classes: macrofossils, mesofossils

Collected in 2014

Primary reference: M. Boivin, L. Marivaux, F. Pujos, R. Salas-Gismondi, J. V. Tejada-Lara, R. M. Varas-Malca, and P.-O. Antoine. 2018. Early Oligocene caviomorph rodents from Shapaja, Peruvian Amazonia. Palaeontographica Abteilung A 311(1-6):87-156 [P. Mannion/P. Mannion]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 199560: authorized by Philip Mannion, entered by Philip Mannion on 31.01.2019, edited by Grace Varnham

Creative Commons license: CC0 (CC0)