Has anyone claimed to have seen a dinosaur?

In 1986 an expedition was exploring the world largest unexplored swamp on earth, the Likoula Swamp in the Congo.

While near Lake Tele, Rory Nugent claimed he saw a long thin neck come up out of the water. He said the animal most resembled a sauropod dinosaur. Local legend talk of a small sauropod called Mokele-mbembe.