''Chelonoidis'' is a genus of turtles in the

tortoise Tortoises ( ) are reptiles of the family Testudinidae of the order Testudines (Latin for "tortoise"). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like o ...

family erected by

Leopold Fitzinger Leopold Joseph Franz Johann Fitzinger (13 April 1802 – 20 September 1884) was an Austrian zoologist. Fitzinger was born in Vienna and studied botany at the University of Vienna under Nikolaus Joseph von Jacquin. He worked at the Vienna Naturhis ...

in 1835. They are found in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

and the

Galápagos Islands The Galápagos Islands () are an archipelago of volcanic islands in the Eastern Pacific, located around the equator, west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of sli ...

, and formerly had a wide distribution in the

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

. The multiple subspecies of the

Galápagos tortoise The Galápagos tortoise or Galápagos giant tortoise (''Chelonoidis niger'') is a very large species of tortoise in the genus ''Chelonoidis'' (which also contains three smaller species from mainland South America). The species comprises 15 subsp ...

(''C. niger'') are among the largest

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

terrestrial chelonians. Giant members of the genus, such as Lutz's giant tortoise (''C. lutzae'') were also present in mainland South America and the West Indies during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, and the latter into the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

Taxonomy

They were formerly assigned to ''

Geochelone ''Geochelone'', from Ancient Greek γῆ (''gê''), meaning "earth", and χελώνη (''khelṓnē''), meaning "turtle", is a genus of tortoises. ''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be ...

'', but a 2006 genetic analysis indicated that they were actually most closely related to hingeback tortoises. However, a more recent genetic analysis of

mtDNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in ...

has found that they are actually most closely related to the lineage containing ''

Centrochelys ''Centrochelys'' is a genus of tortoise. It contains one living species, the African spurred tortoise (''Centrochelys sulcata''), native to the Sahel and adjacent areas. A number of fossil species have been attributed to this genus, but their p ...

'' and ''

''. Their ancestors apparently floated across the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

from

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

in the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

. This crossing was made possible by their ability to float with their heads up and to survive up to six months without food or water. Based on

analysis, the extant ''Chelonoidis'' members can be divided into two lineages, with one containing the

red-footed tortoise The red-footed tortoise (''Chelonoidis carbonarius'') is a species of tortoise from northern South America. These medium-sized tortoises generally average as adults, but can reach over . They have dark-colored (nearly black), “loaf”-shaped ...

(''C. carbonarius'') and

yellow-footed tortoise The yellow-footed tortoise (''Chelonoidis denticulatus''), 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 (''C. carbonarius''). It is found in the ...

(''C. denticulatus''), and the other containing the Chaco tortoise (''C. chilensis'') and the Galapagos tortoises (''C. niger''). The now-extinct West Indian radiation is thought to group with the Chaco and Galapagos tortoises but is significantly basal to both, and was a rather evolutionary distinct lineage, having diverged well before any of the modern species in the genus did and only 7 mya after the divergence of ''Chelonoidis'' from African tortoises. A 2021 study found that the extent of divergence among the species in the Galápagos and Bahamian ''Chelonoidis'' radiations may have been overestimated, and supported subsuming many of the species in both complexes to being subspecies of two parent species; '' C. alburyorum'' for the

Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...

and

Turks and Caicos Islands The Turks and Caicos Islands (abbreviated TCI; and ) are a British Overseas Territory consisting of the larger Caicos Islands and smaller Turks Islands, two groups of tropical islands in the Lucayan Archipelago of the Atlantic Ocean and no ...

, and '' C. niger'' for the Galápagos. This was followed by the

Turtle Taxonomy Working Group The Turtle Taxonomy Working Group (TTWG) is an informal working group of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group (TFTSG). It is composed of a number of leading turtle taxonomists, with varying participation by individual partici ...

and the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared ...

in 2021. The names of several species names in the genus have often been misspelled, beginning in the 1980s when ''Chelonoidis'' was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.

Distribution

Presently, ''Chelonoidis'' are distributed throughout most of

, as well as most of the Galápagos; the genus extended north into

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

during the

and most of the

up to the late

. ''C. carbonarius'' and ''C. denticulatus'' are presently found on some of the Lesser Antillean islands, but the provenance of these individuals is unknown, and they could have been introduced by

Amerindians In the Americas, Indigenous peoples comprise the two continents' pre-Columbian inhabitants, as well as the ethnic groups that identify with them in the 15th century, as well as the ethnic groups that identify with the pre-Columbian population of ...

during

pre-Columbian In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...

times.

In the West Indies

In prehistoric times, a large insular radiation of giant ''Chelonoidis'' existed on many West Indian islands, including the

Greater Antilles The Greater Antilles is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, and Jamaica, together with Navassa Island and the Cayman Islands. Seven island states share the region of the Greater Antille ...

and Lesser Antilles. While some species such as those on

Curaçao Curaçao, officially the Country of Curaçao, is a constituent island country within the Kingdom of the Netherlands, located in the southern Caribbean Sea (specifically the Dutch Caribbean region), about north of Venezuela. Curaçao includ ...

Anguilla Anguilla is a British Overseas Territories, British Overseas Territory in the Caribbean. It is one of the most northerly of the Leeward Islands in the Lesser Antilles, lying east of Puerto Rico and the Virgin Islands and directly north of Sa ...

, and

Barbados Barbados, officially the Republic of Barbados, is an island country in the Atlantic Ocean. It is part of the Lesser Antilles of the West Indies and the easternmost island of the Caribbean region. It lies on the boundary of the South American ...

are thought to have gone extinct during the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

, other species such as those on the Greater Antilles and the Bahamas are thought to have been driven to extinction after the first

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s arrived on the islands, from 7000 BC onwards. The Bahamian tortoise (''C. alburyorum'') was one of the last-surviving of these species, persisting up to 1170 AD on the Abacos, up to 1200 AD on

Grand Turk Grand Turk is an island in the Turks and Caicos Islands, a British Overseas Territory, tropical islands in the Lucayan Archipelago of the Atlantic Ocean and northern West Indies. It is the largest island in the Turks Islands (the smaller of th ...

, and up to 1400 AD on the

Middle Caicos Middle Caicos is the largest island in the Turks and Caicos Islands. To the west, it is separated from North Caicos by Juniper Hole, and to the east, from East Caicos by Lorimer Creek, both narrow passages that can accommodate only small boats. ...

, just under a century prior to European colonization of the islands.Turtle Extinctions Working Group (Rhodin, A.G.J., Thomson, S., Georgalis, G., Karl, H.-V., Danilov, I.G., Takahashi, A., de la Fuente, M.S., Bourque, J.R., Delfino, M., Bour, R., Iverson, J.B., Shaffer, H.B., and van Dijk, P.P.). 2015
Turtles and tortoises of the world during the rise and global spread of humanity: first checklist and review of extinct Pleistocene and Holocene chelonians.
Chelonian Research Monographs 5(8) A 2017 study found that some of these species such as those from

Hispaniola Hispaniola (, also ) is an island between Geography of Cuba, Cuba and Geography of Puerto Rico, Puerto Rico in the Greater Antilles of the Caribbean. Hispaniola is the most populous island in the West Indies, and the second-largest by List of C ...

were specialists adapted to dry, open habitats such as

Hispaniolan dry forests The Hispaniolan dry forests are a tropical dry broadleaf forest ecoregion on the island of Hispaniola (split between the Dominican Republic and Haiti). They cover , around 20% of the island's area. Geography The dry forests are found mostly on ...

and had a major role in shaping them; following a decrease in the extent of these ecosystems after the end of the

, these tortoises were restricted to refugia habitats up until their extinction. A 2021 study identified two distinct genetic lineages within the Bahaman tortoise, ''C. alburyorum'', but also sometimes found the remains of members of both lineages on the same island, even though the lineages would have only separated with geographic isolation. This indicates that the early inhabitants of the West Indies were successfully transporting the large tortoises across islands, presumably for the purpose of consumption, and thus causing the remains geographically-isolated lineages to co-occur on the same islands.

''Chelonoidis'' species

Note that the genus name ''Chelonoidis'' is masculine under the rules of the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its formal author, t ...

, and adjectival species names must agree in gender; the species names below are displayed in keeping with this rule, and may differ from how they commonly appear in publications.

Extant and recently extinct species

Listed alphabetically: *'' C. carbonarius'' –

*''Chelonoidis chilensis, C. chilensis'' – Chaco tortoise *''Yellow-footed tortoise, C. denticulatus'' –

*''Galápagos tortoise, C. niger'' –

– with the following subspecies: ** ''Pinta Island tortoise, C. n. abingdonii'' – Pinta Island tortoise (extinct as of 2012, but could be bred back from hybrids and/or persist as lone individuals) ** ''Volcán Wolf giant tortoise, C. n. becki'' – Volcán Wolf giant tortoise ** ''Chelonoidis chathamensis, C. n. chathamensis'' – San Cristobal giant tortoise ** ''Santiago Island giant tortoise, C. n. darwini'' – Santiago Island giant tortoise ** ''Chelonoidis donfaustoi, C. n. donfaustoi'' – eastern Santa Cruz tortoise ** ''Pinzón Island giant tortoise, C. n. duncanensis'' – Pinzon Island giant tortoise ** ''Chelonoidis guntheri, C. n. guntheri '' – Sierra Negra giant tortoise ** ''Chelonoidis hoodensis, C. n. hoodensis'' – Hood Island giant tortoise ** ''Chelonoidis microphyes, C. n. microphyes '' – Volcán Darwin giant tortoise ** ''Chelonoidis niger, C. n. niger'' – Floreana giant tortoise (driven to extinction in the mid-19th century, but could be bred back from hybrids) ** ''Fernandina Island Galápagos tortoise, C. n. phantasticus'' – Fernandina Island tortoise (rediscovered in February 2019) ** ''Chelonoidis porteri, C. n. porteri'' – western Santa Cruz tortoise **Santa Fe Island tortoise, ''C.'' ''n.'' 'Santa Fe Island lineage' – Santa Fe Island tortoise (Undescribed taxon, undescribed, driven to extinction in the mid-19th century) ** ''Chelonoidis vandenburghi, C. n. vandenburghi'' – Volcán Alcedo giant tortoise ** ''Chelonoidis vicina, C. n. vicina'' – Cerro Azul giant tortoise * '' C. alburyorum'' – Bahamian tortoise (Late

of The Bahamas and Turks and Caicos Islands, Turks & Caicos Islands) * ''Chelonoidis cubensis, C. cubensis'' – Cuban giant tortoise (Early Holocene of Cuba) * ''Chelonoidis gersoni, C. gersoni'' (

-Holocene,

) * ''Chelonoidis marcanoi, C. marcanoi'' (=''C. dominicensis'') (Pleistocene-Holocene, Hispaniola) * ''Chelonoidis monensis, C. monensis'' – Mona tortoise (Late Holocene of Isla de Mona, Puerto Rico) Relationships of the genus, after Kehlmaier et al, 2017 and 2021.

Fossil species

Late Quaternary fossil species

Listed alphabetically: * ''Chelonoidis lutzae, C. lutzae –'' Lutz’s giant tortoise (

of Argentina) * ''Chelonoidis marcanoi, C. marcanoi'' (Quaternary of the Dominican Republic) (''nomen dubium'' as holotype fossil does not allow for distinguishing between species) * ''Chelonoidis somberensis, C. pucara '' (Late Pleistocene of Buenos Aires province, Argentina) * ''Chelonoidis somberensis, C. sombrerensis'' – Sombrero giant tortoise (Late Pleistocene of Sombrero, Anguilla, Sombrero,

)

Other fossil species

Listed alphabetically: * ''Chelonoidis australis, C. australis'' (Miocene to Pliocene of Argentina) * ''Chelonoidis gallardoi, C. gallardoi'' (Miocene of Argentina, Late Pleistocene of Ecuador) * † ''Chelonoidis gringorum, C. gringorum'' (Miocene of Argentina) * † ''Chelonoidis hesternus, C. hesternus'' (Miocene of Colombia)

References

{{Taxonbar, from=Q2080003 Chelonoidis, Turtle genera Taxa named by Leopold Fitzinger