Mammal site (Telm 5) (Eocene of Antarctica)

Where: Antarctica (64.2° S, 56.6° W: paleocoordinates 64.0° S, 59.7° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Telm 5 Member (La Meseta Formation), Bartonian (41.3 - 38.0 Ma)

• Mammal site is lower Telm5. The age model for the La Meseta Formation (and recently-defined Submeseta Formation) is controversial. Strontium isotopes (Ivany et al., 2008) suggest earlier ages, with the La Meseta (Telm1-Telm5) almost entirely Ypresian and the Submeseta (Telm6-Telm7) Middle-Late Eocene. Montes et al. (2013) also created an age model incorporating magnetostratigraphy to support the largely-Ypresian age for the La Meseta and Middle-Late Eocene for the Submeseta. Some mammals are similar to the radiometrically-constrained late early Eocene Paso del Sapo assemblage of Patagonia (Gelfo et al., 2009, Tejedor et al., 2009), but the mammals are not exactly similar (Bond et al., 2011). However, Douglas et al. (2014) re-evaluated the strontium data and used dinoflagellate biostratigraphy to argue for a Lutetian (Telm2-4) and younger (Bartonian to mid-Priabonian for Telm5-6) age range. Amenábar et al. (2019) also found younger ages from dinoflagellates: Lutetian (Telm1-mid Telm 3), Bartonian (mid Telm 3-mid Telm 5), and Priabonian (upper Telm 5), SPDZ10-SPDZ13. This age range is more consistent with the presence of basilosaurid whales in Telm4 and Telm7, as basilosaurids are globally-distributed first in the middle Eocene (Buono et al., 2016). Although the ages are still debated, the dinoflagellate age model of Amenábar et al. (2019) is used here.

• group of beds-level stratigraphic resolution

Environment/lithology: paralic; poorly lithified sandstone

• The environment of deposition of this complex unit has been subject to different interpretations, all agreeing in general that Telm5 represents a shallow-marine setting. A study by Wiedman and Feldmann (1988) on the ichnofossil fauna and depositional environment of the La Meseta Formation concluded that the Telm5 setting was a littoral to very shallow sublittoral clastic marine terrain, definitely above storm base and most probably above normal wave base. They agreed with Elliot and Trautrnan (1982) that Units II and III probably represent a tidally dominated environment, but evidence from sedimentary structures is also consistent with a barrier bar model and does not represent a shallowing upward sequence. Elliot and Trautman (1982) favored a deltaic model. The analysis of trace fossils and body fossils (including vertebrate remains and large, abundant wood fragments) indicates variable nearshore, shallow-marine environments. A scenario for the depositional environment could include a combination ebb-tidal (or possibly flood-tidal) delta-barrier island complex (Stilwell & Zinsmeister, 1992).
• Thinly bedded arkosic sandstone

Size classes: macrofossils, mesofossils

Collected by Argentine-Polish expedition in 1987, 1988

• Repository: Institute of Paleobiology of the Polish Academy of Sciences

Primary reference: J. Dzik and A. Gazdzicki. 2001. The Eocene expansion of nautilids to high latitudes. Palaeogeography, Palaeoclimatology, Palaeoecology 172:297-312 [M. Clapham/K. Okamoto/M. Clapham]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 180207: authorized by Matthew Clapham, entered by Matthew Clapham on 11.07.2016

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Cephalopoda
 Nautilida - Aturiidae
Aturia sp.
Aturia sp. Bronn 1838 nautiloid