First cetotheriid baleen whales from the south Atlantic

AZUCENA SOLÍS-AÑORVE; MÓNICA R. BUONO; FELIX MARX

Virtual Meeting

Otro; 9th International Meeting on the Secondary Adaptation of Tetrapods to Life in Water Virtual Meeting; 2021

Cetotheriidae are a family of small- to medium-sized baleen whales with an unusual cranial anatomy. After long being considered extinct, some analyses now suggest that the pygmy right whale, Caperea marginata, may be their last living representative. Cetotheriid fossils are known from the Miocene to the Pleistocene, and ranged across the Paratethys, North Pacific, North Atlantic and the South East Pacific. In South America, they are well represented along the Pacific coasts of Chile and Peru, but so far have remained conspicuously absent from the Atlantic. Here, we report their first record from the late Miocene of Patagonia, Argentina (Puerto Madryn Formation; 11.9-9 Ma, Serravallian-Tortonian). The new specimens include an isolated left periotic resembling that of Herentalia, and left and right tympanic bullae of uncertain affinity. Our findings broaden the diversity of mysticetes in the Miocene assemblage of Patagonia and notably expand the geographical range of cetotheriids in the Southern Hemisphere. In addition, the presence of a genus previously only known from the North Atlantic invites a reevaluation of cetotheriid biogeography.*Project supported by Grant N° 893338 from Consejo Nacional de Ciencia y Tecnología (CONACYT)