Dinopedia
Advertisement

Megantereon is a machairodont felid from early Pliocene to middle Pleistocene North America, Eurasia, and Africa. It may have been the ancestor of the later Smilodon.

Taxonomy and Discovery

Megantereon was first discovered in 1824 when paleontologist and naturalist Georges Cuvier used two teeth from this cat in conjunction with another from Machairodus to recontrruct and describe a new species of extinct animal. Amazingly, Cuvier believed the specimens to belong, erroneously, to a bear. Four years later, the jaw of a Megantereon was discovered by Croizet and Jobert at the fossil site of Les Etouaires, and again erroneously described to belong to belong to a bear known as "Ursus cultridens", as no one in the nineteenth century had ever seen a cat with elongated teeth. Eventually, Megantereon was lumped in with Machairodus as a member of the genus, but Italian paleontologist G. Ficcarelli was able to finally discern decades of taxonomic lumping, and concluded that the name Megantereon cultridens had the priority over all others attributed to it.

Fossil fragments have been found in Africa, Eurasia, and North America. The oldest confirmed records of Megantereon are known from the Pliocene of North America and are dated to about 4.5 million years. About 3-3.5 million years ago, it is firmly recorded also from Africa (for example, in Kenya), about 2.5 to 2 million years ago also from Asia. In Europe the oldest remains are known from Les Etouaries (France), a site which is now dated to less than 2.5 million years old. Therefore, a North American origin of Megantereon has been suggested. However, recent findings of fragmentary fossils from Kenya and Chad, which are dated to about 5.7 and 7 million years, respectively, are probably from Megantereon. If these identifications are right, they would represent the oldest Megantereon fossils in the world. The new findings therefore indicate an origin of Megantereon in the Late Miocene of Africa.

Therefore, the true number of species may be less than the full list of described species reproduced below.

  • Megantereon cultridens (type species)
  • Megantereon ekidoit 
  • Megantereon hesperus 
  • Megantereon inexpectatus 
  • Megantereon microta 
  • Megantereon nihowanensis 
  • Megantereon vakhshensis 
  • Megantereon whitei

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.

Paleobiology

Teeth and jaw

Megantereon was built like a large modern jaguar, but was somewhat heavier. It had stocky forelimbs with the lower half of these forelimbs being 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 fully specimen found at Seneze in France as 72 centimetres (28 in) at the shoulder. The largest specimens, with an estimated body weight of 90–150 kilograms (200–330 lb) (averaging 120 kilograms (260 lb) in weight), 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 60–70 kilograms (130–150 lb). 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 100 kilograms (220 lb) for the smaller specimens. In agreement with that, more recent sources estimated Megantereon from the European lower Pleistocene at 100–160 kilograms (220–350 lb).

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.

In popular culture

Gallery

Advertisement