Livyatan melvillei is an extinct genus and species of odontocete, belonging to the superfamily Physeteroidea, known from different fossils found on the coast of the Pacific Ocean, in what is now Peru and Chile.
Its fossils were found for the first time in the Pisco desert, Ica Region, in rocks 12-13 million years ago (Miocene). The fossil remains of 75% of the skull and large fragments of the jaws were found, as well as several teeth (the largest measured 36 cm in length, much longer than the current sperm whale). Its skull was about 3 meters long and the total length must have been 13.5 to 17.5 meters. Later, teeth of the species were reported in the Bahía Inglesa Formation, in Chile, which were 12 cm in diameter and 36 cm long.