The oldest mammals from Antarctica, early Eocene of the La Meseta Formation, Seymour Island

• Published in: Palaeontology
• Main Authors: Gelfo, Javier N., Mörs, Thomas, Lorente, Malena, López, Guillermo M., Reguero, Marcelo
• Other Authors: O'Regan, Hannah, ANPCyT-Agencia Nacional de Promoción Científica y Tecnológica, CONICET-Consejo Nacional de Investigaciones Científicas y Técnicas, Swedish Research Council, Swedish Polar Research Secretariat
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Paleontology; Ecology, Evolution, Behavior and Systematics; Antarc*; Antarctica; Seymour Island
• Online Access: http://dx.doi.org/10.1111/pala.12121; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fpala.12121; https://onlinelibrary.wiley.com/doi/pdf/10.1111/pala.12121; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/pala.12121

Abstract New fossil mammals found at the base of A cantilados II A llomember of the L a M eseta F ormation, from the early E ocene ( Y presian) of S eymour I sland, represent the oldest evidence of this group in A ntarctica. Two specimens are here described; the first belongs to a talonid portion of a lower right molar assigned to the sparnotheriodontid litoptern N otiolofos sp. cf. N . arquinotiensis . Sparnotheriodontid were medium‐ to large‐sized ungulates, with a wide distribution in the E ocene of S outh A merica and A ntarctica. The second specimen is an intermediate phalanx referred to an indeterminate E utheria, probably a S outh A merican native ungulate. These A ntarctic findings in sediments of 55.3 Ma query the minimum age needed for terrestrial mammals to spread from S outh A merica to A ntarctica, which should have occurred before the final break‐up of G ondwana. This event involves the disappearance of the land bridge formed by the W eddellian I sthmus, which connected W est A ntarctica and southern S outh A merica from the L ate C retaceous until sometime in the earliest P alaeogene.