New 43-Foot Mosasaur, Tylosaurus rex, Rewrites Sea Predator History

Paleontologists describe a gigantic new mosasaur, Tylosaurus rex, up to 43 feet long with serrated teeth, discovered mainly in Texas. Larger than the previously known Tylosaurus proriger, it indicates a formidable open-water predator in North America’s Western Interior Seaway, with several famous museum specimens reclassified under the new species and findings published in the Bulletin of the American Museum of Natural History.