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, CECILIA R.; ARNAUDO, E. ; BONA, P. ; BUONO M. ; CÁRDENAS, M. ; CHORNOGUBSKY, L. ; CONSTANTINI, O. ; GELFO, J.; GOUIRIC-CAVALLI, S. ; MOLY, J. ; O?GORMAN, J. ; PUERTA, P. ; SANTILLANA, S. ; TALEVI, M.

Kuala Lumpur

Conferencia; XXIV SCAR Meetings and Open Science Conference; 2016

The Scientific Committee on Antarctic Research

During December2015 / February 2016, within the activities of the ?Vertebrate Paleontology ofthe James Ross Basin, Antarctic Peninsula? project of the Instituto AntárticoArgentino, 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 andterrestrial vertebrates. An exceptional (over 2000 m thick) latest Cretaceousto Eocene shallow ? marginal marine sedimentary sequence is exposed on SeymourIsland, 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 bythe Sobral Formation (Paleocene), the Cross Valley Formation (?Late Paleocene),the La Meseta Formation (early-middle Eocene), and the Submeseta (late Eocene).New extensivecollections of vertebrate fossils from Seymour Island include late EoceneSubmeseta 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 lateMaastrichtian López de Bertodano Formation telesotean fishes, sharks,plesiosaurs, mosasaurs and dinosaurs. The taxonomy, ecology and biostratigraphyof these fossils will be analyzed and the results aim to the paleoenvironmentalreconstruction and identifying the oceanographic changes that occurred prior tothe Gondwana break up and after the demise of the connections betweenAntarctica and South America.Also we reportthe discovery of a new marine fossil assemblage from the marine Jurassic sites ofLonging Cape, eastern Antarctic Peninsula. It includes fishes, ichthyosaurs andplesiosaurs, and is one of the richest Jurassic marine biotic assemblages foundin Antarctica.