Homotheria ( Latin Homotherium ) is an extinct genus of saber-toothed cats that lived in Eurasia , Africa and North America from the Middle Pliocene (3–3.5 million years ago) to the end of the Late Pleistocene (10 thousand years ago). The extinction of homotherias began from Africa, from where these cats disappeared about 1.5 million years ago, in Eurasia this genus died out about 30 thousand years ago [1] , and the species Homotherium serum lasted the longest in North America - until the end of the Pleistocene, about 10 thousand years ago.
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 Skeleton homotherium at the Museum of the University of Texas at Austin | ||||||||||||||||||||
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| Homotherium Fabrini, 1890 | ||||||||||||||||||||
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† Homotherium aethiopicum |
According to the study of mitochondrial DNA of saber-toothed cats from the subfamily Machairodontinae, the evolutionary paths of the genera Smilodon and Homotherium diverged about 18 million years ago. All American and European Late Pleistocene (post- Willafrancian ) homotherium samples belonged to the same species Homotherium latidens . One of the reasons that led the saber-toothed cats to extinction was their low genetic diversity [2] [3] .
Anatomy
The growth of homotherias reached 1.1 m at the withers, that is, they reached the size of a lion , the weight was about 190 kg [4] [5] . Compared to some other saber-toothed cats, like smilodons or meganterons , homotherias had relatively short upper fangs , but they were wider and had notches. In contrast, incisors of homotherium were larger than those of smilodons and reached large sizes. Among modern felines, only a tiger has such large incisors that help in raising and transferring prey. The molars of homotheria were rather weak and not suitable for cracking large bones. The skull was longer than that of Smilodon and had a well-developed sagittal crest , where powerful muscles were attached, which set the lower jaw in motion. She had characteristic processes that protected the upper fangs with a closed mouth.
Outwardly, the homotherium was slightly different from other large cats. The forelimbs were slightly longer than the hind limbs. The structure of the hind limbs of homotherium indicates that he jumped worse than modern cats. The pelvic area , including the sacral vertebrae , looked like a bear . The short tail consisted of 13 vertebrae. Thus, physically homotherium was like a hyena .
The unusually large, square nasal passages, like that of a cheetah , provided faster oxygen uptake needed to cool the brain. Another similarity is the developed visual region of the brain, which emphasizes the ability to see well during the day, and not at night, like most cats.
However, unlike the cheetah, homotherium was far from being such a fast runner. Judging by the physique, the homotherium was a fairly hardy animal (by the standards of cats) and was adapted for long-term running in open spaces.
Range and Species
Homoterias, apparently, descended from the Machairodus in the Middle Pliocene, according to various sources - 3 or 3.5 million years ago. In the Pleistocene era, homotheria populated vast territories of Eurasia, North America, and Africa. The fossilized remains of homotherium, 1.8 million years old, were also found in Venezuela [6] [7] , which indicates that homotherias, along with smilodons, entered South America during the Great Inter-American Exchange . However, how long they existed on this continent is not yet clear.
Several types of homotherium are known in Eurasia: H. nestianus, H. sainzelli, H. crenatidens, H. nihowanensis, H. ultimum. These species differ among themselves mainly in the shape of their fangs and body size. However, given the large size variation among modern large cats, it is possible that all of the above species belong to the same species - Homotherium latidens.
I must also say that some scientists classify one species of the mahairod, Machairodus davitashvilii from the late Pliocene of Georgia , as the genus Homotherium. This species is characterized by a narrow skull and fangs that are very long for homoteria. Perhaps this saber-toothed cat is a kind of transitional form from the makhairodov to homotheria.
Two types of homotherium existed in the Early Pleistocene in Africa - H. ethiopicum and H. hadarensis, but they hardly differ from the Eurasian forms. Homoteria died out on the African continent about 1.5 million years ago. In North America, a very similar species, H. serum, appeared in the Late Pliocene and lived to the end of the Pleistocene. The remains of this species were found in various areas between Alaska and Texas . In the southern parts of its range, H. serum coexisted with smilodon, but in the northern regions it was the only species of saber-toothed cat. This species was originally described under the name Dinobastis.
Despite the wide range of homotherium and a large number of its fossils, the full skeletons of this predator are relatively rare. One of the most famous locations of the remains of homotherium is the Friesenhahn Cave in Texas, where more than 30 skeletons of the homotherium were discovered, along with hundreds of skeletons of cub mammoths and several terrible wolves .
Fossils of homotheria in North America are found less than the remains of his contemporary smilodon. It is likely that homotherium led a solitary or, in extreme cases, a family lifestyle, and occupied a different ecological niche . The northern border of the range of homotherium passed higher than that of Smilodon.
Presumably, homotherias preyed on young proboscis , rhinos and other large animals. A decrease in the number of homotherias could occur with the gradual extinction of these giant herbivores.
Notes
- ↑ Reumer, JWF; L. Rook, K. Van Der Borg, K. Post, D. Mol, J. De Vos. Late Pleistocene survival of the saber-toothed cat Homotherium in northwestern Europe (Eng.) // Journal of Vertebrate Paleontology : journal. - Society of Vertebrate Paleontology 2003. - Vol. 23 . - P. 260 . - ISSN 0272-4634 . - DOI : 10.1671 / 0272-4634 (2003) 23 [260: LPSOTS] 2.0.CO; 2 .
- ↑ Ancient DNA offers new view on saber-toothed cats' past , 2017
- ↑ Evolutionary History of Saber-Toothed Cats Based on Ancient Mitogenomics , 2017
- ↑ Sorkin, B. 2008: A biomechanical constraint on body mass in terrestrial mammalian predators. Lethaia, Vol. 41, pp. 333—347
- ↑ Meade, GE 1961: The saber-toothed cat Dinobastis serus . Bulletin of the Texas Memorial Museum 2 (II), 23-60.
- ↑ Sanchez, Fabiola Saber-toothed Cat Fossils Discovered in Venezuela (inaccessible link - history ) . Associated Press (August 22, 2008). Date of treatment August 30, 2008.
- ↑ Orozco, José Sabertooth Cousin Found in Venezuela Tar Pit - A First . National Geographic News . National Geographic Society (August 22, 2008). Date of treatment August 30, 2008. Archived August 31, 2012.