Megantereon

''Megantereon'' was a genus of prehistoric machairodontine saber-toothed cat that lived in North America, Eurasia, and Africa. It may have been the ancestor of ''Smilodon''.

Taxonomy

Fossil fragments have been found in Africa, Eurasia, and North America. It also ranged into southernmost China as well, as a mostly complete skull from Sabretooth Cave, Chongzuo indicates, though it seemed to have been rare in most of Asia due to being ill-adapted to closed forest environments. The oldest confirmed records of ''Megantereon'' are known from the Pliocene of Africa.

Therefore, the true number of species may be less than the full list of described species reproduced below:
* ''Megantereon cultridens'' (Cuvier, 1824) (type species)
* ''Megantereon adroveri'' Pons Moya, 1987
* ''Megantereon ekidoit'' Werdelin & Lewis, 2000
* ''Megantereon falconeri'' Pomel, 1853
* ''Megantereon hesperus'' (Gazin, 1933)
* ''Megantereon microta'' Zhu ''et al.'', 2015
* ''Megantereon vakhshensis'' Sarapov, 1986
* ''Megantereon whitei'' Broom, 1937

However, as of 2022 it was proposed, alongside the description of more material, that there were more Asian species than just ''M. falconeri'': ''M. nihowanensis'', ''M. inexpectatus'' (syn. ''M. lantianensis''), and ''M. megantereon'' (syn. ''M. microta''). However, the authors disregarded ''M. falconeri'' due to that species' poor record, and also noted that two specimens- a skull in the Natural History Museum of London and a skull in a museum in Dublin- likely represented a new species (which had been previously noted by other authors).

Evolution

At the end of the Pliocene it evolved into the larger ''Smilodon'' in North America, while it survived in the Old World until the middle Pleistocene. The youngest remains of ''Megantereon'' from east Africa are about 1.5 million years old. In southern Africa, the genus is recorded from Elandsfontein, a site dated to around 700,000–400,000 years old. Remains from Untermaßfeld show that ''Megantereon'' lived until 900,000 years ago in Europe. In Asia, it may have survived until 500,000 years ago, as it is recorded together with ''Homo erectus'' at the famous site of Zhoukoudian in China. The only full skeleton was found in Senéze, France.

Description

''Megantereon'' was built like a large modern jaguar, but somewhat heavier. It had stocky forelimbs with the lower half of these forelimbs lion-sized. It had large neck muscles designed to deliver a powerful shearing bite. The elongated upper canines were protected by flanges at the mandible. Mauricio Anton's reconstruction in ''The Big Cats and their Fossil Relatives'' depicts the full specimen found at Seneze in France as at the shoulder. The largest specimens, with an estimated body weight of (average ), are known from India. Medium-sized species of ''Megantereon'' are known from other parts of Eurasia and the Pliocene of North America. The smallest species from Africa and the lower Pleistocene of Europe have been estimated to only . However, these estimations were obtained from comparisons of the carnassial teeth. Younger estimations, which are based on the postcranial skeleton, lead to body weights of about for the smaller specimens. In agreement with that, more recent sources estimated ''Megantereon'' from the European lower Pleistocene at .

Palaeobiology

In Europe, ''Megantereon'' may have preyed on larger artiodactyls, horses or the young of rhinos and elephants. Despite its size, ''Megantereon'' would have also likely been scansorial and therefore able to climb trees, like the earlier '' Promegantereon'' (thought to be its ancestor), and unlike the later ''Smilodon'', which is believed to have spent its time on the ground. In addition to this, ''Megantereon'' had relatively small carnassial teeth, indicating that once making a kill, it would have eaten its prey at a leisurely pace, either hidden deep in bushes or up in trees away from potential rivals. This indicates a similarity in lifestyle with modern leopards in that it was probably solitary.

It is unlikely that ''Megantereon'' simply bit its prey as the long, sabre-teeth that ''Smilodon'' is famed for are not strong enough to leave buried inside a struggling prey animal: the teeth would break off, and thus their tactic for killing remains uncertain.

It is now generally thought that ''Megantereon'', like other saber-toothed cats, used its long saber teeth to deliver a killing throat bite, severing most of the major nerves and blood vessels. While the teeth would still risk damage, the prey animal would be killed quickly enough that any struggles would be feeble at best.

At Dmanisi, Georgia, evidence also exists in the form of a '' Homo erectus'' skull that ''Megantereon'' interacted with hominids as well. The skull, labelled as D2280, shows wounds to the occipital that match the dimensions of the sabre-teeth of ''Megantereon''. From the placement of the bite marks, it can be implied that the hominid was attacked from the front and top of the skull, and that the bite was likely placed by a cat that saw the hominid as a rival: other machairodont bites have been found on rival predators in past fossil discoveries, including other machairodonts; wounds indicative of aggressive behavior towards perceived competition. The hominid likely managed to escape the ''Megantereon'', as no evidence points to predation or scavenging, but the resulting wounds proved fatal. Further evidence exists in the form of carbon isotope ratios in the teeth for ''Megantereon'' being a hunter of hominids at Swartkrans. When compared with its fellow machairodont, '' Dinofelis'', which shared the same environment, it was discovered that ''Megantereon'' was more likely to prey on hominids than ''Dinofelis'', which preferred to hunt grazing animals based on carbon isotope ratios of its own teeth.

References

Further reading

* Augustí, Jordi. ''Mammoths, Sabertooths and Hominids: 65 Million Years of Mammalian Evolution in Europe''. New York: Columbia University Press, 2002, .
* Mol, Dick, Wilrie van Logchem, Kees van Hooijdonk and Remie Bakker. ''The Saber-Toothed Cat of the North Sea''. Uitgeverij DrukWare, Norg 2008, .
* Turner, Alan. ''The Big Cats and Their Fossil Relatives: An Illustrated Guide to their Evolution and Natural History''. Illustrations by Mauricio Anton. New York: Columbia University Press, 1997, .

{{Taxonbar, from=Q133945

Smilodontini
Pliocene carnivorans
Pleistocene carnivorans
Messinian genus first appearances
Pleistocene genus extinctions
Miocene mammals of Africa
Pliocene mammals of Asia
Pliocene mammals of Europe
Pliocene mammals of Africa
Pliocene mammals of North America
Pleistocene mammals of Asia
Pleistocene mammals of Europe
Pleistocene mammals of Africa
Pleistocene mammals of North America
Prehistoric carnivoran genera
Fossil taxa described in 1828