Family Testudinidae (Tortoises)

Order Testudines
Suborder Cryptodira
Superfamily Testudinoidea

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Family Testudinidae (Tortoises)

Geochelone denticulata.

Appearance: They have high domed shells and stout, heavily scaled limbs (Malacochersus is an exception with a dorsoventrally compressed shell). The head and limbs can be fully withdrawn into the shell. The genera Testudo and Pyxis have hinged plastrons while members of the genus Kinyxis have, uniquely among tortoises, a hinged carapace that allows it to be lowered over the hindquarters.

Size: 10 - 125 cm carapax length. Gigantism has evolved independently in several island populations, with those of the Galapagos and Aldabra islands being the most famous.

Distribution: Testudinids are land turtles that occur mainly in Africa in Asia although a few species are known from the Americas and Europe.

Food: predominantly herbivorous or omnivorous

Habitat: Tortoises are mainly arid-adapted.

Behaviour: Juvenile turtles tend to be cryptic, because their shell doesn't protect them from predators yet.

Reproduction: About 12 eggs in Testudo graeca and Testudo (= Agrionemys) horsfieldii. the latter deposits its eggs in July and the young hatch only 9 months later (April). In contrast, the young of Testudo kleinmanni hatch already after 20 days.

Relationships: Sometimes the Batagurinae have been included as subfamily in the Testudinidae, although they are also dconsidered as separate family, Bataguridae, or as subfamily of the Emydidae.

Taxonomic notes: Geochelone is considered as a subgenus of Testudo by Wermuth & Mertens (1977), but as a valid genus by Ernst & Barbour (1989). The species list given bellow follows mainly Ernst & Barbour (1989).

Geochelone, Asterochelys, Chelonoidis, Megalochelys, and Testudo are used synonymously to some extent. Check species list of Geochelone and Testudo. The giant tortoises of Galapagos (Geochelone elephantopus ssp.) have been subdivided in a series of separate species. The Indian Ocean giant tortoises (genus Cylindraspis) seem to be extinct now (Arnold 1979, Bour 1980). Cylindraspis contains at least 5 species: borbonica (Réunion), triserrata, inepta (both Mauritius), vosmaeri, peltastes (both Rodrigues) (AUSTIN et al. 2002).

Subgenera of Testudo according to Wermuth & Mertens (1977): Acinixys, Agrionemys, Asterochelys, Chelonoidis, Chersina, Geochelone, Indotestudo, Manouria, Megalochelys, Psammobates, Pseudotestudo, Testudo.