New records of marine turtles (Testudines: Chelonioidea) from the Miocene of Chubut, Argentina

STERLI, JULIANA; VLACHOS, EVANGELOS; CUITIÑO, JOSÉ I.; BUONO, MÓNICA R.; VIGLINO, MARIANA; BESSONE, SANTIAGO; PUERTA, PABLO

Congreso; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2018

Extinct turtles associated to marine environments in Argentina have a discontinuous record since the Late Jurassic to the Miocene. These turtlesadapted to marine environments belong to different clades: the extinct Platychelyidae (Pan-Pleurodira) and Thalassochelyidia (Pan-Cryptodira), andthe extant Chelonioidea (formed by two clades: Dermochelyidae and Cheloniidae). The study of fossil marine turtles has its own challenges, as thecosmopolitan distribution of the extant taxa, and probably the extinct as well, makes any fossil of marine turtles relevant beyond its regional context.Up to now, only fragmentary and undetermined specimens of dermochelyids were known for the Miocene marine deposits of Chubut. Recentfieldworks leaded by researchers from CENPAT have brought to light an almost complete shell with some postcranial elements of a dermochelyidturtle from Estancia La Redonda Chica (near Trelew). Also, some fragmentary remains were collected in Bryn Gwyn Geopark (near Gaiman). Apartial shell and postcranial remains from Punta Buenos Aires and a partial skull (Península Valdés), and a beak (Bryn Gwyn Geopark) are the firstrecords of pan-cheloniids in Chubut. All the specimens were unearthed from Miocene shallow shelf deposits of the Gaiman Formation (earlyMiocene) and Puerto Madryn Formation (late Miocene). These findings are promising, as they will provide valuable information on the anatomy,taxonomy and diversity of the marine turtles that once populated the seas and coasts of Chubut