查看文章

The first appearance and evolution of the crown group Cetacea – Mysticeti (baleen whales) and Odontoceti (toothed whales and dolphins) – from archaeocete ancestors corresponds with major climatic and oceanographic changes shortly before the Eocene–Oligocene boundary (ca. 34.0 Ma). These environmental changes impacted marine productivity and may have sparked the evolution of the distinct bulk-feeding strategy used by mysticete whales today. The movements and feeding habits of living cetaceans can be tracked using the isotopic composition of the structural carbonate within bioapatite of their bones and teeth, which records latitudinal gradients in marine δ¹³C and δ¹⁸O values. Here, we exploit this relationship to determine the past movements and feeding habits of late-surviving archaeocetes (kekenodontids) and early odontocetes and mysticetes sampled from Oligocene fossil sites in the USA …