Filling the palaeobiogeographic gap in mysticetes evolution: new records of baleen whales from the Neogene of the Atacama region, southeastern Pacific, Chile

CAROLINA SIMON GUTSTEIN; MÓNICA R. BUONO

Virtual Meeting

Congreso; 64th Annual Meeting of the Palaeontological Association -Virtual Meeting; 2020

Mysticetes are an iconic group of marine mammals that include the most gigantic microphagous vertebrates that have ever lived on Earth. The fossil record of baleen whales dates back to the early Oligocene, reaching a diversification and widespread distribution during the Miocene, being present along most of the oceans (Atlantic, North and Southwestern Pacific, and the Mediterranean). However, along the Southeastern Pacific, especially in the Chilean coast, the fossil record of baleen whales is still mysterious. We increased fieldwork effort in the last years in the Neogene Bahía Inglesa and Coquimbo formations, and performed critical review of fossil specimens from National collections. At least three groups of mysticetes were recognized from diagnostic materials (skulls; tympano-periotic): Cethotheriidae (c.f. Herpetocetus sp.), Balaenidae (Balaena sp.) and Balaenopteroidea (Balaenoptera sp.). Both cethotheriids and balaenids records are the first ones for the Southeastern Pacific coast, greatly expanding their geographical distributions during the late Miocene. In the case of balaenids, presently unrepresented in the area, the new record implicates a contraction on the distribution of right whales after the Neogene. Contrasting with their scarce representation in coeval formations along the Southwestern Atlantic coast (Argentina), balaenopteroids are the most abundant mysticete remains in chilean Miocene deposits.