Kongamato

A creature of the Jiundu swamp in western Zambia, recorded in 1923 as a river danger that floods fords, and later described as a pterosaur-like cryptid.

Frank H. Melland wrote about the kongamato in In Witch-Bound Africa (1923), a book on the Kaonde people and their beliefs. In a chapter on charms he describes a danger at fords and ferries on some rivers. The kongamato, he writes, lives below the crossing and can hold the water back, so the level rises suddenly and swamps whoever is crossing. Wikipedia glosses the name as "overwhelmer of boats". For protection, Melland says, a traveller ground mulendi tree root and mixed it with water in a bark cup, and carried a bundle of root strips in the canoe or while wading the ford.

Melland also lists the Jiundu swamp among the places the kongamato was said to live. He describes roughly fifty square miles of swampland, where the Jiundu River splits into many channels in an inland delta and then joins again downstream as one clear stream. If such a reptile could exist anywhere, he wrote, this would be the place.

Wikipedia says local people and researchers have reported seeing it in the Jiundu swamps of Zambia's Mwinilunga district, and in Angola and the Democratic Republic of the Congo. Suggested identities include a surviving pterosaur, a giant bat, or a bird such as the saddle-billed stork. Skeptics, it says, put the sightings down to known animals that look prehistoric. Writing in Skeptical Inquirer on claimed prehistoric survivors, Sharon Hill notes it is sometimes described as a possible living rhamphorhynchoid pterosaur with a long thin tail tipped with a diamond shape.