Kalpana Kalpana (Editor)

Livyatan

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Kingdom  Animalia
Order  Artiodactyla
Superfamily  Physeteroidea
Scientific name  Livyatan melvillei
Rank  Species
Phylum  Chordata
Infraorder  Cetacea
Family  incertae sedis
Higher classification  Livyatan
A poster by Harry Wilson comparing the size of a Livyatan melvillei, from Megalodon, Leedsichthys, Liopleurodon, blue whale, giant squid, orca, great white shark, and human.
Similar  Basilosaurus, Megalodon, Brygmophyseter, Kronosaurus, Helicoprion

790 productions colossal squid vs livyatan


Livyatan is an extinct genus of physeteroid whale, similar in size to the modern sperm whale. It contains the single species L. melvillei. It lived during the Serravallian stage of the Miocene epoch, about 12 to 13 million years ago (Mya), though evidence from Australia implies that either it or a close relative survived into the Zanclean stage of the Pliocene, around 5 Mya.

Contents

Livyatan melvillei in the deep ocean with a big mouth.

Ppba sperm whale vs livyatan


Taxonomy

Livyatan melvillei with another kind of marine mammal and a human in the ocean.

In November 2008, fossil remains of L. melvillei were discovered in the coastal desert of Peru in the sediments of the Pisco Formation at Cerro Colorado, 35 km (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 paleontologists.

The fossils have been dated at 12–13 Mya and were prepared in Lima, and are now part of the collection of the Natural History Museum there.

Skull of a prehistoric whale.

Researchers originally assigned the English name of the biblical monster, Leviathan, to this prehistoric whale as Leviathan melvillei, dedicating the discovery to Herman Melville, author of Moby-Dick—the researchers behind the excavation of L. melvillei were all fans of this novel. However, the scientific name Leviathan was a junior homonym of Leviathan Koch, 1841 for a genus of mastodon (see Leviathan in Wikispecies). Junior homonyms need to be replaced with new names, except under certain special circumstances (ICZN 1999 Article 60). In August 2010, the authors rectified this situation by coining a new genus name for the whale, Livyatan, from the original Hebrew spelling.

In 2016, a gigantic physeteroid tooth was discovered among Pliocene-aged sediments in Beaumaris Bay, Australia. The tooth appears to belong to "an extinct species of sperm whale closely related to Livyatan melvillei from Peru". The fossil has not received any official species designation yet. The tooth also dates to around 5-6 Mya. This means that the raptorial sperm whales survived for another 2 million years after the Peruvian L. melvillei occurrence. The large tooth of the whale looks very much like Livyatan and may even be a species of Livyatan.

Description

Livyatan melvillei was 13.5 to 17.5 m (44 to 57 ft) long, about the same as a modern adult male sperm whale. The skull of L. melvillei is 3 m (9.8 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 cm (14 in) long and are thought to among be the largest of any animal yet known, with only a newly discovered relative from the Pliocene having teeth within the size range. Larger 'teeth' (tusks) are known, such as odobenocetops and narwhal tusks, but these are not used directly in eating.

Two physeterids have been chosen by whale experts for comparison to estimate the size of L. melvillei. The anatomy of Physeter macrocephalus yielded a total length (TL) of 13.5 m (44.3 ft) for L. melvillei, and that of Zygophyseter varolai yielded a TL of 17.5 m (57.4 ft) for L. melvillei.

In 2016, a large tooth of a whale was found on the coast of Australia. The tooth measured some 30 cm in length, making the owner of the tooth comparable to L.melvillei.

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 this organ apparently 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.

Paleobiology

L. melvillei was an apex predator along with the giant shark, C. megalodon, which was contemporaneous with L. melvillei in the same region, and the whale probably had a profound impact on the structuring of Miocene marine communities. The appearance of gigantic raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene.

L. melvillei is likely to have preyed upon 7–10 m (23–33 ft) sharks, baleen whales, seals, dolphins and other large marine vertebrates, which it captured with its long teeth.

Palaeoecology

Fossil remains of many marine vertebrates, including baleen whales, beaked whales, dolphins, porpoises, sharks, sea turtles, seals and sea birds, have been found at the same site where the remains of L. melvillei have been excavated.

References

Livyatan Wikipedia


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