EOCENE BASILOSAURID WHALES FROM THE LA MESETA FORMATION, MARAMBIO (SEYMOUR) ISLAND, ANTARCTICA

MONICA R. BUONO; SERGIO MARENSSI; MARCELO REGUERO; THOMAS MÖRS; MARTA S. FERNÁNDEZ; SERGIO SANTILLANA

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2016 vol. 53 p. 296 - 315

0002-7014

Basal fully aquatic whales, the basilosaurids are worldwide known from Bartonian?Priabonian localities, indicating that this groupwas widely distributed during the late middle Eocene. In the Northern Hemisphere, fossils of basilosaurids are abundant, while records in theSouthern Hemisphere are scarce and, in some cases (i.e., Antarctica), doubtful. The presence of basilosaurids in Antarctica was, until now, uncertain because most of the records are based on fragmentary materials that preclude an accurate assignment to known archaeocete taxa.Here we report the findings of mandibles, teeth, and innominate bone remains of basilosaurids recovered from the La Meseta Formation (TELM4 Lutetian?Bartonian and; TELM 7 Priabonian), in Marambio (Seymour) Island (James Ross Basin, Antarctic Peninsula). These findings confirmthe presence of Basilosauridae in the marine realm of Antarctica, increasing our knowledge of the paleobiogeographic distribution of basilosauridsduring the middle?late Eocene. In addition, one of these records is among the oldest occurrences of basilosaurids worldwide, indicating a rapidradiation and dispersal of this group since at least the early middle Eocene