Cretaceous Period Megalodon Megafauna Woolly Mammoth Genyornis newtoni Species Interactions Megalodon extinction Human Impact Conservation Pleistocene Species Diversity Woolly Mammoths Dinosaur Extinction Peirosaurids Extinction Theories Complex Life Forms Ancient Species Paleobiology Mesozoic Era Prehistoric Life Great Apes Resurrection Ancient Organisms Great White Shark Ichthyosaurs
Multi‑proxy isotopes from three North Dakota teeth point to riverine life enabled by a freshening Western Interior Seaway.