Quantification of Cenozoic Marine Primary Productivity through Geochemical Analysis of Marine Mammal Bioapatite Mark T. Clementz, Dept. of Geology & Geophysics, Univ. of Wyo. Pezosiren Dorudon Marine (Today) Rodhocetus Indohyus Marine (Today) Pakicetus Freshwater (Today) Freshwater (Today) Members of the sister taxon (Raoellidae: Indohyus) to whales were semiaquatic, but mostly fed on land. Trophic position was high: 3rd to 4th order consumers By 50 Ma, foraged in freshwater habitats (Pakicetus) By 46 Ma, foraged in nearhsore marine habitats (Rodhocetus, Dorudon) Favored highly productive waters close to shore Early sirenians were marine consumers of seagrasses with little evidence of freshwater plants in their diets Sirenian trophic position was low and stable: 1st order consumers Favored shallow water marine habitats

Quantification of Cenozoic Marine Primary Productivity through Geochemical Analysis of Marine Mammal Bioapatite Mark T. Clementz, Dept. of Geology & Geophysics, Univ. of Wyo. Metaxytherium Marine (Today) Metaxytherium Marine (Today) Freshwater (Today) Freshwater (Today) In the Neogene, sirenians (yellow) exhibit a greater dietary range than that for Paleogene species (gray) First evidence of freshwater diets from the Middle Miocene. Sirenian trophic position was low and stable: 1st order consumers High number of sympatric species in the West Atlantic-Caribbean Region No isotopic evidence of freshwater diets for Miocene cetaceans Trophic diversity increased: 2nd –4th order consumers Diversification of modern baleen (Mysticeti) and toothed (Odontoceti) whales High carbon isotope values indicate these species still favored high productivity waters that were closer to shore than those of extant species