An apparent sauropod dinosaur
The Mokele-Mbembe, of Central Africa, seems to live in one of the most inaccessible tropical areas in the world: a giant swamp: the Likouala. The creature reported in descriptions strongly suggesting it's a sauropod dinosaur (walking on four legs).

According to a web page saying that the creature is a "living dinosaur,"
"In the jungles of central Africa countries of Congo, Cameroon, and Gabon are reports of animal an animal with a long neck, a long tail, and rounded shape tracks with three claws. The closest known animal that has these characteristics is a sauropod dinosaur."