Aldabrachelys grandidieri

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Aldabrachelys grandidieri
Temporal range: Holocene
Testudo grandidieri madagascar.JPG
Upper side of carapace
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Testudinidae
Genus: Aldabrachelys
Species:
A. grandidieri
Binomial name
Aldabrachelys grandidieri
(Vaillant, 1885)
Synonyms [1]
  • Emys giganteaGrandidier, 1868
  • Testudo grandidieriVaillant, 1885(nomen novum)
  • Testudo madagascariensisRothschild, 1915
  • Geochelone grandidieri(Vaillant, 1885)
  • Asterochelys grandidieri(Vaillant, 1885)
  • Dipsochelys grandidieri(Vaillant, 1885)

Aldabrachelys grandidieri, or Grandidier's giant tortoise, is an extinct species of tortoise that was endemic to Madagascar. Mitochondrial DNA extracted from subfossil bone confirm that it is a distinct species. [1] [2]

Contents

Description

Underside of carapace Aldabrachelys grandidieri 45.jpg
Underside of carapace

Aldabrachelys grandidieri was a giant tortoise, one of the largest in the world, measuring about 125 cm (49 in) in carapace length. It was originally one of the six endemic tortoise species of Madagascar (two large Aldabrachelys ; two medium Astrochelys ; two small Pyxis ).

It is distinguished from all other Aldabrachelys by a massive, flattened or depressed carapace, bulging sides of the carapace, short gulars, top of the nasal aperture is higher than the top of orbits, diverging quadrates, broad postorbitals, and a very large processus vomerinus dorsalis. It also had an unusually thick, strong carapace, possibly an adaptation to heavy predation. It seems to have been predominantly a grazer of meadows and wetlands. [1]

Extinction

Material of this species has been dated to 1250–2290 years before present. It seems to have gone extinct relatively soon after the later migration of humans arrived from the mainland of Africa. Unlike its more common sister species, the abrupt giant tortoise ( Aldabrachelys abrupta (also extinct)), the massive grandidieri did not seem to have succeeded in coexisting with humans for any length of time. [1] [2]

Ecology

Aldabrachelys grandidieri (along with Aldabrachelys abrupta) likely were seed dispersers of the six baobab ( Adansonia spp.) species endemic to Madagascar; in an experiment, extant Aldabra giant tortoises (Aldabrachelys gigantea) readily consumed fruit of Adansonia rubrostipa . [3] Other ecological functions of giant tortoises likely included trampling and selectively consuming vegetation. It is suggested that introduced Aldabra giant tortoises could be used for restoration of these functions. [4]

Related Research Articles

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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.

<span class="mw-page-title-main">Aldabra</span> Coral atoll in the Indian Ocean

Aldabra is the world's second-largest coral atoll, lying southeast of the continent of Africa. It is part of the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120 km (700 mi) southwest of the capital, Victoria on Mahé Island. Initially named by Arab seafarers for its harsh environment, Aldabra became a French colony dependency in the 18th century, leading to the exploitation of its natural resources, particularly giant tortoises. After passing through British hands, Aldabra faced potential military use in the 1960s, but international protests resulted in its protection. The atoll boasts unique geography, featuring the world's largest raised coral reef and a large shallow lagoon. Aldabra's history involves human impact, including failed agricultural ventures. Post-World War II, conservation efforts increased, leading to its inclusion in the British Indian Ocean Territory and eventual independence for Seychelles. Following an international protest by scientists known as the 'Aldabra Affair,' the Royal Society of London and later the Seychelles Islands Foundation conducted research, leading to Aldabra's declaration as a UNESCO World Heritage Site in 1982. The atoll's flora and fauna, notably the giant tortoises, comprise an 'ecological wonder', with Aldabra serving as a critical breeding ground for various species. Conservation challenges, such as invasive species and plastic pollution, persist, but protective measures, including UNESCO designation, underscore Aldabra's significance as a natural vital scientific research site. Aldabra receives limited tourism to safeguard its delicate ecosystem and is accessible primarily through guided tours.

<span class="mw-page-title-main">Giant tortoise</span> Several species of land tortoise

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.

<i>Adansonia</i> Genus of plants known as baobab

Adansonia is a genus made up of eight species of medium-to-large deciduous trees known as baobabs. They are placed in the Malvaceae family, subfamily Bombacoideae. They are native to Madagascar, mainland Africa, and Australia. The trees have also been introduced to other regions such as Asia. The generic name honours Michel Adanson, the French naturalist and explorer who described Adansonia digitata. The baobab is also known as the "upside down tree", a name that originates from several myths. They are among the most long-lived of vascular plants and have large flowers that are reproductive for a maximum of 15 hours. The flowers open around dusk, opening so quickly that movement can be detected by the naked eye, and are faded by the next morning. The fruits are large, oval to round and berry-like and hold kidney-shaped seeds in a dry, pulpy matrix.

<span class="mw-page-title-main">Aldabra giant tortoise</span> Species of tortoise

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<i>Aldabrachelys</i> Genus of tortoises

Aldabrachelys is genus of giant tortoises, including the Aldabra giant tortoise native to the Seychelles, as well as two extinct species, Aldabrachelys abrupta and Aldabrachelys grandidieri known from Madagascar.

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Adansonia grandidieri is the biggest and most famous of Madagascar's six species of baobabs. It is sometimes known as Grandidier's baobab or the giant baobab. In French it is called Baobab malgache. The local name is renala or reniala. This tree is endemic to the island of Madagascar, where it is an endangered species threatened by the encroachment of agricultural land. This is the tree found at the Avenue of the Baobabs.

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References

  1. 1 2 3 4 Aldabrachelys grandidieri at the Reptarium.cz Reptile Database. Accessed 16 May 2015.
  2. 1 2 Austin, J. J.; Arnold, E. N.; Bour, R. (2003). "Was there a second adaptive radiation of giant tortoises in the Indian Ocean? Using mitochondrial DNA to investigate speciation and biogeography of Aldabrachelys (Reptilia, Testudinidae)". Molecular Ecology. 12 (6): 1415–1424. Bibcode:2003MolEc..12.1415A. doi:10.1046/j.1365-294X.2003.01842.x. PMID   12755871. S2CID   1518514.
  3. Andriantsaralaza, S.; Pedrono, M.; Tassin, J.; Roger, E.; Rakouth, B.; Danthu, P. (2014). "The role of extinct giant tortoises in the germination of extant baobab Adansonia rubrostipa seeds in Madagascar" (PDF). African Journal of Ecology. 52 (2): 246–249. Bibcode:2014AfJEc..52..246A. doi:10.1111/aje.12101.
  4. Pedrono, M.; Griffiths, O. L.; Clausen, A.; Smith, L. L.; Griffiths, C. J.; Wilmé, L.; Burney, D. A. (2013). "Using a surviving lineage of Madagascar's vanished megafauna for ecological restoration". Biological Conservation. 159: 501–506. Bibcode:2013BCons.159..501P. doi:10.1016/j.biocon.2012.11.027.