Paleontological inheritance of West Antarctica: Preliminary report of the newly found Mesozoic and Cenozoic fossil vertebrates from the James Ross Basin and Antarctic Peninsula

REGUERO M, ACOSTA BURLAILLE, L, ACOSTA HOSPITALECHE, C, AMENABAR, C, ARNAUDO E, BONA, P, BUONO M, CÁRDENAS, M, CHORNOGUBSKY, L, CONSTANTINI, O, GELFO, J, GOUIRIC-CAVALLI, S, MOLY, J, OGORMAN, J, PUERTA P, SANTILLANA S, TALEVI, M.

Kuala Lumpur

Conferencia; Scar 2016. Open Science Conference; 2016

During December 2015 / February 2016, within the activities of the ?Vertebrate Paleontology of the James Ross Basin, Antarctic Peninsula? project of the Instituto Antártico Argentino, principal fossiliferous localities of Seymour Island (marine Late Cretaceous, K-Pg and Paleogene outcrops), northeast Antarctic Peninsula) and Cape Longing (marine Jurassic), Antarctic Peninsula were prospected seeking for marine and terrestrial vertebrates. An exceptional (over 2000 m thick) latest Cretaceous to Eocene shallow ? marginal marine sedimentary sequence is exposed on Seymour Island, located then and now at ~65°S. The López de Bertodano Formation (uppermost Cretaceous to lowermost Paleocene) contains the K?Pg boundary (identified using biostratigraphy and an iridium anomaly) and is overlain by the Sobral Formation (Paleocene), the Cross Valley Formation (?Late Paleocene), the La Meseta Formation (early-middle Eocene), and the Submeseta (late Eocene). New extensive collections of vertebrate fossils from Seymour Island include late Eocene Submeseta Formation primitive mysticeti skeleton, sharks, and birds; early-middle Eocene La Meseta Formation telesotean fishes, sharks, birds, terrestrial mammals, early Paleocene Sobral Formation telesotean fishes and sharks, and late Maastrichtian López de Bertodano Formation telesotean fishes, sharks, plesiosaurs, mosasaurs and dinosaurs. The taxonomy, ecology and biostratigraphy of these fossils will be analyzed and the results aim to the paleoenvironmental reconstruction and identifying the oceanographic changes that occurred prior to the Gondwana break up and after the demise of the connections between Antarctica and Sout America.Also we report the discovery of a new marine fossil assemblage from the marine Jurassic sites of Longing Cape, eastern Antarctic Peninsula. It includes fishes, ichthyosaurs and plesiosaurs, and is one of the richest Jurassic marine biotic assemblages found in Antarctica.