Scientists in Argentina have identified a new megaraptoran dinosaur, about 23 feet long, from Patagonia's Lago Colhué Huapi formation. The 66-70 million-year-old fossil includes skull, arm, leg, and tail bones, with a crocodile relative's limb pressed against its jaws. This rare find could yield some clues to its diet and whether it was top predator on the humid prehistoric floodplains.