Tortoises are reptiles of the family Testudinidae of the order Testudines. Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like other members of the suborder Cryptodira, they retract their necks and heads directly backward into the shell to protect them.
Chelydra is one of the two extant genera of the snapping turtle family, Chelydridae, the other being Macrochelys, the much larger alligator snapping turtle. The snapping turtles are native to the Americas, with Chelydra having three species, one in North America and two in Central America, one of which is also found in northwestern South America.
Elseya is a genus of large side-necked turtles, commonly known as Australian snapping turtles, in the family Chelidae. Species in the genus Elseya are found in river systems in northern and northeastern Australia and throughout the river systems of New Guinea. They are identified by the presence of alveolar ridges on the triturating surfaces of the mouth and the presence of a complex bridge strut.
Manouria is a genus of tortoises in the family Testudinidae. The genus was erected by John Edward Gray in 1854.
Hesperotestudo is an extinct genus of tortoise native to North and Central America from the Early Miocene to the Late Pleistocene. Species of Hesperotestudo varied widely in size, with a large undescribed specimen from the Late Pleistocene of El Salvador reaching 150 cm (4.9 ft) in carapace length, larger than that of extant giant tortoises. Historically considered a subgenus of Geochelone, it is now considered to be distantly related to that genus. Its relationships with other tortoises are uncertain. The exposed areas of the bodies of Hesperotestudo species were extensively covered with large dermal ossicles, which in life were covered in keratin. It has been suggested that species of Hesperotestudo were relatively tolerant of cold weather. Hesperotestudo became extinct at the end of the Pleistocene roughly co-incident with the arrival of the first humans in North America. There is apparently a site in Florida where one individual may have been killed that some suggested were evidence of butchering, although others suggested that the turtle was neither cooked nor does a ledge that was found near it date at the same time as it.
Chelonoidis is a genus of turtles in the tortoise family erected by Leopold Fitzinger in 1835. They are found in South America and the Galápagos Islands, and formerly had a wide distribution in the West Indies.
The Chaco tortoise, also known commonly as the Argentine tortoise, the Patagonian tortoise, or the southern wood tortoise, is a species of tortoise in the family Testudinidae. The species is endemic to South America.
Aldabrachelys abrupta, the abrupt giant tortoise, is an extinct species of giant tortoise that was endemic to Madagascar.
Megalochelys is an extinct genus of tortoises that lived from the Miocene to Pleistocene. They are noted for their giant size, which is among the largest of any known testudine, with a maximum carapace length over 2 m (6.5 ft) in M. atlas. During the dry glacial periods it ranged from western India and Pakistan to as far east as Sulawesi and Timor in Indonesia, though the island specimens likely represent distinct species.
Centrochelys atlantica is an extinct species of tortoise that lived in the Pleistocene. It was first recorded in the volcanic crater on Sal, Cape Verde. It was initially identified as similar to the extant Testudo calcarata. The species is no longer present anywhere in the Cape Verde islands. It has since been described as a new species, differentiated from C. sulcata by its smaller size and lesser robusticity. It does not seem there is any evidence this species came into contact with humans. Kehlmaier et al. (2021) identified the type material of this species as belonging to a specimen of the red-footed tortoise, making C. atlantica a junior synonym of the latter species and leaving the extinct tortoise known from fossils excavated on the Sal Island in the 1930s without a scientific name.
The Tenerife giant tortoise is an extinct species of cryptodire turtle in the family Testudinidae endemic to the island of Tenerife, in the Canary Islands.
The Gran Canaria giant tortoise is an extinct species of cryptodire turtle in the family Testudinidae endemic to the island of Gran Canaria, in the Canary Islands.
Centrochelys is a genus of tortoise. It contains one extant species and several extinct species:
Scott A. Thomson is an Australian herpetologist, paleontologist, and taxonomist, specialising in turtles of the family Chelidae.
Chelonoidis niger phantasticus is a subspecies of Galápagos tortoise that was discovered in 1906 and thought extinct, until a single female was discovered living on Fernandina Island by an expedition in February 2019. In May 2021, a genetic test carried out by scientists from the California Academy of Sciences confirmed that the single female tortoise discovered in 2019 is from the subspecies Chelonoidis niger phantasticus. The subspecies name has often been misspelled as phantastica, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
Phrynops paranaensis is an extinct species of turtle from the Huayquerian Ituzaingó Formation of the Paraná Basin, Argentina, likely to be late Miocene in origin.
Chelonoidis alburyorum is an extinct species of giant tortoise that lived in the Lucayan Archipelago from the Late Pleistocene to around 1400 CE. The species was discovered and described by Richard Franz and Shelley E. Franz, the findings being published in 2009.
Solitudo is an extinct genus of tortoise that was found during the Pliocene and Pleistocene on the Mediterranean islands of Menorca, Malta and Sicily. The genus includes three described species, Solitudo robusta, Solitudo gymnesica and Solitudo sicula as well as a likely fourth, undescribed species from Monte Pellegrino in Sicily. Solitudo sicula, the youngest of the species, died out approximately 12.5 thousand years BP. The largest species, Solitudo gymnesica, has been estimated to have reached a carapace length of 1.1–1.3 m (3.6–4.3 ft).
Chelonoidis cubensis, also known as the Cuban giant tortoise, is an extinct species of land tortoise that lived in Cuba from the Late Pleistocene to the Early Holocene. It had a carapace length of between 40 cm and 90 cm. It is thought that the species went extinct through human exploitation.
