Livyatan melvillei is an extinct species of physeteroid whale, similar in size to the modern sperm whale. It lived during the Serravallian stage of the Miocene epoch, approximately 12 to 13 million years ago.
In November 2008, fossil remains of Livyatan melvillei were discovered in the coastal desert of Peru in the sediments of the Pisco formation at Cerro Colorado, 35 kilometres (22 mi) south-southwest of Ica. The remains include a partially preserved skull with teeth and mandible. Rotterdam Natural History Museum researcher Klaas Post stumbled across them on the final day of a field trip there in November 2008. Post was part of an international team of palaeontologists.
The fossils have been dated at 12–13 million years old and were prepared in Lima, Peru, and are now part of the collection of the Natural History Museum there.
Description & behaviour
Livyatan melvillei was 13.5 to 17.5 metres (44–57 ft) long, about the same as a modern adult male sperm whale. The skull of Livyatan melvillei is 3 metres (10 ft) long. Unlike the modern sperm whale, Physeter macrocephalus, L. melvillei had functional teeth in both of its jaws. The jaws of L. melvillei were robust and its temporal fossa was also considerably larger than in the modern-age sperm whale. L. melvillei is one of the largest predators yet known, with whale experts using the phrase "the biggest tetrapod bite ever found" to explain their find. The teeth of L. melvillei are up to 36 centimetres (1.18 ft) long and are thought to be the largest of any animal yet known. Larger 'teeth' (tusks) are known, such as walrus and elephant tusks, but these are not used directly in eating.
The fossil skull of L. melvillei has a curved basin which suggests it might have had a large spermaceti organ, a series of oil and wax reservoirs separated by connective tissue. This organ is thought to help modern sperm whales to dive deeply to feed. However, L. melvillei is likely to have hunted large prey near the surface, so it appears that this organ would have had other functions. Possible suggestions include echolocation, acoustic displays (with the spermaceti organ acting as a resonance chamber) or aggressive headbutting, possibly used against competing males in mating contests or to batter prey.