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.
Giant tortoises are any of several species of various large land tortoises, which include a number of extinct species, as well as two extant species with multiple subspecies formerly common on the islands of the western Indian Ocean and on the Galápagos Islands.
The Greek tortoise, also known commonly as the spur-thighed tortoise, is a species of tortoise in the family Testudinidae. Testudo graeca is one of five species of Mediterranean tortoises. The other four species are Hermann's tortoise, the Egyptian tortoise, the marginated tortoise, and the Russian tortoise. The Greek tortoise is a very long-lived animal, achieving a lifespan upwards of 125 years, with some unverified reports up to 200 years.
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.
The Galápagos tortoise or Galápagos giant tortoise is a very large species of tortoise in the genus Chelonoidis. The species comprises 15 subspecies. It is the largest living species of tortoise, with some modern Galápagos tortoises weighing up to 417 kg (919 lb). They are also the largest extant terrestrial ectotherms.
The yellow-footed tortoise, also known as the Brazilian giant tortoise, is a species of tortoise in the family Testudinidae and is closely related to the red-footed tortoise. It is found in the Amazon Basin of South America. The species name has often been misspelled as denticulata, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
Hadrianus is an extinct genus of tortoise belonging to the Testudinidae found in the United States, the Yolomécatl Formation of Mexico, the Alai Beds of Kyrgyzstan and Spain and believed to be the oldest true tortoise known. The genus is thought to be closely related to the genus Manouria. The genus may have evolved in the subtropics of Asia and subsequently migrated to North America and Europe. Evangelos Vlachos (2018) reassessed the North American species attributed to the genus, and determined only two as accepted namely H. corsoni & H. majusculus. The remaining species were identified as either junior synonyms, moved to other genera or considered nomen dubium do to incomplete fossils.
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.
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.
The Alachua Formation is a Miocene geologic formation in Florida. The claystones, sandstones and phosphorites of the formation preserve many fossils of mammals, birds, reptiles and fish, among others megalodon.
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.
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.
Titanochelon is an extinct genus of giant tortoises known from the Early Miocene to the beginning of the Pleistocene in Europe, extending from the Iberian Peninsula to Anatolia. Some members of the genus were larger than extant giant tortoises, with a shell length of up to 2 m.
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).
