The earliest Gavialoidea may or may not have been related to the modern types: some died out at the same time as the dinosaurs (at the end of the Cretaceous), others survived until the early Eocene (about 35 million years ago). The modern forms appeared at much the same time. They evolved in the estuaries and coastal waters of Africa. They crossed the Atlantic to reach South America as well. At their peak, the Gavialoidea were numerous and diverse, they occupied much of Asia and America up until the Pliocene. One species, "Rhamphosuchus crassidens" of India, is believed to have grown to an enormous 15 metres or more.