Tooth fossil found at Smithsonian turns out to be from ancient hippo-like creature

A pair of paleobiologists with the Smithsonian Institution's National Museum of Natural History has found evidence of a long extinct herbivore marine mammal living in what is now the Skooner Gulch Formation in northern California. In their paper published in the journal Royal Society Open Science, Kumiko Matsui and Nicholas Pyenson describe their study of an uncatalogued tooth they found among the Institution's massive collection and what they learned about it.