RESEARCH ARTICLE Stomach contents of the archaeocete Basilosaurus isis: Apex predator in oceans of the late Eocene 1☯ 2³ 3³ 3☯ Manja VossID *, Mohammed Sameh M. Antar , Iyad S. Zalmout , Philip D. Gingerich 1 Museum fuÈr Naturkunde Berlin, Leibniz-Institute for Evolution and Biodiversity Science, Berlin, Germany, 2 Department of Geology and Paleontology, Nature Conservation Sector, Egyptian Environmental Affairs Agency, Cairo, Egypt, 3 Museum of Paleontology, University of Michigan, Ann Arbor, Michigan, United States of America a1111111111 a1111111111 ☯ These authors contributed equally to this work. a1111111111 ³ These authors also contributed equally to this work. a1111111111 *
[email protected] a1111111111 Abstract Apex predators live at the top of an ecological pyramid, preying on animals in the pyramid OPEN ACCESS below and normally immune from predation themselves. Apex predators are often, but not Citation: Voss M, Antar MSM, Zalmout IS, always, the largest animals of their kind. The living killer whale Orcinus orca is an apex pred- Gingerich PD (2019) Stomach contents of the ator in modern world oceans. Here we focus on an earlier apex predator, the late Eocene archaeocete Basilosaurus isis: Apex predator in oceans of the late Eocene. PLoS ONE 14(1): archaeocete Basilosaurus isis from Wadi Al Hitan in Egypt, and show from stomach con- e0209021. https://doi.org/10.1371/journal. tents that it fed on smaller whales (juvenile Dorudon atrox) and large fishes (Pycnodus pone.0209021 mokattamensis). Our observations, the first direct evidence of diet in Basilosaurus isis, con- Editor: Carlo Meloro, Liverpool John Moores firm a predator-prey relationship of the two most frequently found fossil whales in Wadi Al- University, UNITED KINGDOM Hitan, B.