Machairodus is a large saber-toothed cats, reach the size of a lion, with elongated upper canines and cheek teeth adapted for cutting of meat.
Machairodus genus first appeared in Eurasia in the Middle Miocene about 15 million years ago, and ends its existence in Tunisia, where the sediment age of about 2 million years old have been found material relating to the Machairodus africanus. In European sediment age of about 10 Ma appearance known as Machairodus aphanistus, very common finding. The same species in the future could live in Asia. Recent discoveries in Spain (Cerro Batallones, near Madrid, Miocene epoch) now allow a full picture, based on the nearly complete skeletal material. This species is probably the same animal, as well known in North America the Nimravides catacopsis, good specimens of which are found in the Early Pliocene deposits of Kansas, Texas and Florida.
At various times in the literature indicated other species of Machairodus, but now it is unclear the exact number of species, the reasonableness of the allocation of which can be proved.
However, despite the fact that the number of species in the genus are not well defined, within the genus looming presence of two lines of development. Line of the more primitive members of the genus in Europe presented a Machairodus aphanistus, and in North America - the Nimravides species. These animals have a tiger like proportions. Profiles of the skulls were less direct than that of late Machairodus, making these Machairodonts looks more like a Feline, although when compared with modern cats their skulls look very narrow from the front.
Evolutionarily more developed another line, including Eurasian M. giganteus and very similar to it American M.coloradensis, showing further development Machairodont features in the skull and teeth morphology. For example, features such as a flat canines and blade like cheek teeth, reduced coronoid process of the mandible and elongated mastoid of temporal bone. In the development of the skeleton of the second line species of the most notable is the elongation of the forelimbs.
Different species of Machairodus demonstrate evolution toward extreme specialization that observed in the Homotherium genus, which is believed to be the heir of the Machairodus. Russian paleontologist Marina Sotnikova suggested that a new species Machairodus kurteni from Kazakhstan could be a candidate as the Homotherium ancestor.
Overall, the genus remains common primitive features, which are most noticeable in the dental morphology, as jaws of the Machairodus retain more teeth, and in some body proportions.
In the text used material from the book "The Big Cats and Their Fossil Relatives", Alan Turner, Mauritio Anton.