Genus Kinixys

Bell, 1827
Hinge-back tortoises

The six members of the African genus Kinixys are the only living turtles in which the carapace contains a movable hinge. This hinge always lies between the 4th and 5th costals and the 7th and 8th peripherals in adults and allows the posterior portion of the carapace to be lowered over the hindquarters. The carapace is usually elongate and may show some expansion and serration of both the anterior and posterior marginals. It is somewhat domed (depressed in one species), flat topped, and has sloped sides. A slight medial keel may be present in younger individuals, and the anterior neurals are six sided. One or two suprapygal bones are present; if two, these are separated by a straight transverse suture. Nine to twelve marginal scutes occur on each side, submarginal scutes are present, and the supracaudal is divided in one species. The hingeless plastron contains only a shallow anal notch, if at all. Its forelobe is much longer than the hindlobe, and the epiplastra are thickened, but usually not protruding beyond the carapacial rim. The entoplastral bone lies anterior to the humero-pectoral seam. Axillary and inguinal buttresses are short, especially the inguinal which supports the anterior carapace at the hinge. The skull is relatively long with a hooked upper jaw. Triturating surfaces of the jaws lack ridges, and the sides of the jaws are not serrated. The maxillae do not contribute to the roof of the palate, and the anterior palatine foramina are large. The temporal arch is relatively weak. The prootic bone is well-exposed dorsally and the quadrate bone surrounds the stapes. The limbs are not nearly as club shaped as in other testudinids; each forefoot has four or five claws.

Species identification
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