tortoise
Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like oth ...
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
and the
Galápagos Islands
The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...
, and formerly had a wide distribution in the
West Indies
The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greate ...
.
The multiple subspecies of the
Galápagos tortoise
The Galápagos tortoise or Galápagos giant tortoise (''Chelonoidis niger'') is a species of very large tortoise in the genus ''Chelonoidis'' (which also contains three smaller species from mainland South America). It comprises 15 subspecies ( ...
are among the largest extant 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 ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
.
Taxonomy
They were formerly assigned to ''
Geochelone
''Geochelone'' is a genus of tortoises.
''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be found in southern Asia. They primarily eat plants. Species
The genus consists of two extant species:
A ...
'', 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 or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...
has found that they are actually most closely related to the lineage containing ''
Centrochelys
''Centrochelys'' is a genus of tortoise. It contains one extant species and several extinct species:
* ''Centrochelys atlantica''
* ''Centrochelys burchardi''
* ''Centrochelys marocana''
* ''Centrochelys robusta''
* ''Centrochelys vulcanica''
* ...
'' and ''
Geochelone
''Geochelone'' is a genus of tortoises.
''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be found in southern Asia. They primarily eat plants. Species
The genus consists of two extant species:
A ...
''. Their ancestors apparently floated across the
Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
from
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
to
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
in the Oligocene. 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
mtDNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...
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, loaf-shaped carapaces (back shell ...
(''C. carbonarius'') and
yellow-footed tortoise
The yellow-footed tortoise (''Chelonoidis denticulatus''), also known as the Brazilian giant tortoise, commonly referred to as the Brazilian giant turtle, or more commonly, the big turtle, is a species of tortoise in the family Testudinidae and ...
(''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 island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...
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 n ...
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 Taxonomy (biology), taxonomists, with varying participation b ...
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 dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...
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
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
, as well as most of the Galápagos; the genus extended north into
Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
during the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
and most of the
West Indies
The West Indies is a subregion of North America, surrounded by the North Atlantic Ocean and the Caribbean Sea that includes 13 independent island countries and 18 dependencies and other territories in three major archipelagos: the Greate ...
up to the late
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
. ''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
The Indigenous peoples of the Americas are the inhabitants of the Americas before the arrival of the European settlers in the 15th century, and the ethnic groups who now identify themselves with those peoples.
Many Indigenous peoples of the Am ...
during
pre-Columbian
In the history of the Americas, the pre-Columbian era spans from the original settlement of North and South America in the Upper Paleolithic period through European colonization, which began with Christopher Columbus's voyage of 1492. Usually, ...
times.
In the West Indies
In prehistoric times, a large insular radiation of giant ''Chelonoidis'' existed on many West Indian islands, including the
Bahamas
The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...
,
Greater Antilles
The Greater Antilles ( es, Grandes Antillas or Antillas Mayores; french: Grandes Antilles; ht, Gwo Zantiy; jam, Grieta hAntiliiz) is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, Jamaica, a ...
and Lesser Antilles. While some such as those on Curaçao,
Anguilla
Anguilla ( ) is a 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 Saint Martin. The terr ...
, and
Barbados
Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of the Americas, and the most easterly of the Caribbean Islands. It occupies an area of and has a population of about 287,000 (2019 estimate) ...
are thought to have gone extinct during the Late Pleistocene, 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'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
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. T ...
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
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
, 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, 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.
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, loaf-shaped carapaces (back shell ...
yellow-footed tortoise
The yellow-footed tortoise (''Chelonoidis denticulatus''), also known as the Brazilian giant tortoise, commonly referred to as the Brazilian giant turtle, or more commonly, the big turtle, is a species of tortoise in the family Testudinidae and ...
Galápagos tortoise
The Galápagos tortoise or Galápagos giant tortoise (''Chelonoidis niger'') is a species of very large tortoise in the genus ''Chelonoidis'' (which also contains three smaller species from mainland South America). It comprises 15 subspecies ( ...
Pinta Island tortoise
The Pinta Island tortoise (''Chelonoidis niger ''), also known as the Pinta giant tortoise, Abingdon Island tortoise, or Abingdon Island giant tortoise, was a subspecies of Galápagos tortoise native to Ecuador's Pinta Island.
The subspecies wa ...
(extinct as of 2012, but could be bred back from hybrids and/or persist as lone individuals)
** '' C. n. becki'' –
Volcán Wolf giant tortoise
The Volcán Wolf giant tortoise (''Chelonoidis niger becki)'', also known commonly as the Wolf Volcano giant tortoise and the Cape Berkeley giant tortoise, is a subspecies of Galápagos tortoise in the family Testudinidae. The subspecies is nat ...
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
of
The Bahamas
The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to 88% of the ar ...
and
Turks & 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 ...
Cuba
Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
Plio-Pleistocene
The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5&nb ...
to early Holocene of the
Dominican Republic
The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...
Isla de Mona
Mona ( es, Isla de Mona) is the third-largest island of the Puerto Rican archipelago, after the main island of Puerto Rico and Vieques. It is the largest of three islands in the Mona Passage, a strait between the Dominican Republic and Puerto R ...
,
Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...
)
Relationships of the family, after Kehlmaier et al, 2017 and 2021.
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
Sombrero
A sombrero (Spanish , ) is a type of wide-brimmed Mexican men's hat used to shield the face and eyes from the sun. It usually has a high pointed crown, an extra-wide brim (broad enough to cast a shadow over the head, neck and shoulders of the w ...
,
Anguilla
Anguilla ( ) is a 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 Saint Martin. The terr ...
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
to
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58C. gallardoi'' (Miocene of Argentina, Late Pleistocene of
Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...