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MACHAERODUS, or MACHAIRODUS
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See also:MACHAERODUS, or MACHAIRODUS , the typical genus of a See also:group of See also:long-tusked See also:extinct See also:cats, commonly known as sabretooths. Although best regarded as a sub-See also:family (Machaerodontinae) of the Felidae, they are sometimes referred to a See also:separate family under the name Nimravidae (see See also:CARNIVORA). The later forms, as well as some of the earlier ones, are more specialized as regards dentition than the See also:modern Felidae, although in several other respects they exhibit more See also:primitive features. The See also:general type of dentition is feline, but in some instances more premolars are retained, as well as a small tubercular molar behind the See also:lower carnassial. The characteristic feature is, however, the See also:great development of the upper canines, which in the more specialized types reach far below the margin of the lower See also:jaw, despite the development of a flange-like expansion of the extremity of the latter for their See also:protection. In these extreme forms it is quite evident that the jaws could not be used in the See also:ordinary manner; and it seems probable that in attacking See also:prey the lower jaw was dropped to a See also:vertical position, and the huge upper tusks used as stabbing See also:instruments. The group is believed to be derived from a creodont allied to the See also:Eocene Palaeonictis (see See also:CREODONTA). Nimravus, of the See also:American Oligocene, with two premolars and two molars in the lower jaw, and comparatively See also:short upper canines, seems to be the least specialized type; next to which comes Hoplophoneus, another See also:North American Oligocene genus, in which the tubercular lower molar is lost, and the upper canine is longer. It is noteworthy, however, that this genus retains the third trochanter to the femur, which is lost in Nimravus. Machaerodus, in the wider sense, includes the larger and more typical forms. In the See also:Pliocene of See also:France and See also:Italy it is represented by M. megantereon, a See also:species not larger than a See also:leopard, and allied forms occur in the Pliocene of See also:Greece, See also:Hungary, See also:Samos, See also:Persia, See also:India and See also:China, as well as in the See also:Middle See also:Miocene of France and See also:Germany. Far larger is the See also:Pleistocene M. cultridens of the caverns of See also:Europe, with serrated upper tusks several inches in length. From Europe and See also:Asia the sabre-toothed tigers may be traced into North and thence into See also:South See also:America, the See also:home of M. (Smilodon) neogaeus, the largest of the whole tribe, whose remains occur in the Brazilian caves and the silt of the See also:Argentine See also:pampas. This See also:animal was as large as a See also:tiger, with tusks projecting seven inches from the jaw and very complex carnassials; the feet were very short, with only four toes to the See also:hind-pair, and the humerus has lost the foramen at the lower end. Very noteworthy is the occurrence of an imperfectly known specialized type—Eusmilus—in the Lower Oligocene of Europe and perhaps also North America. Unlike all other cats, it had only two pairs of lower incisors, and the large cheek-See also:teeth were reduced to the carnassial and one premolar in advance of the same. (R. Additional information and CommentsThere are no comments yet for this article.
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