Seychelles giant tortoise

Seychelles giant tortoise
Seychelles giant tortoise, La Digue Island
Conservation status
Extinct in the Wild (IUCN 2.3)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Order:	Testudines
Suborder:	Cryptodira
Family:	Testudinidae
Genus:	Aldabrachelys
Species:	A. hololissa
Binomial name
Aldabrachelys hololissa (Günther, 1877)

The Seychelles giant tortoise (Aldabrachelys hololissa) has been thought to be extinct since the mid-19th century due to overexploitation on the granitic Seychelles islands. Similar giant tortoise species on other Indian Ocean islands such as Mauritius, Réunion and Rodrigues Island are also extinct. The only species of Indian Ocean giant tortoise to avoid this fate was the Aldabra giant tortoise due to its isolated location and 19th century conservation efforts.

This species inhabited islands of the Seychelles group, where it thrived on vegetation on the edges of marshes and streams. By 1840, it had disappeared from the wild and was assumed to be extinct. As a grazing species, it somewhat resembled the Aldabra tortoise with its domed shape.

In 1999, some Seychelles island tortoises (12 known individuals) were suggested to have survived in captivity. The report of oddly-shaped captive tortoises prompted the Nature Protection Trust of Seychelles to examine the identity of the living tortoises. Examination of museum specimens of the "extinct" Seychelles species by Dr. Justin Gerlach and Laura Canning seemed to show some living tortoises possess characteristics of the extinct species.

However, recently published scientific papers on the genetics of the Seychelles and Indian Ocean tortoises provide conflicting results. Some studies suggest only one species was present historically, but others support the presence of three closely related species.

A 181-year old tortoise on Saint Helena, named Jonathan, is believed to be a survivor of the species (as well as being potentially the oldest living tortoise in the world presently).^[1]

Seychelles giant tortoises, La Digue Island

References

1. ^ Saint Helena government The Tortoises at Plantation House

• Jeremy J. Austrin, E. Nicholas Arnaud & Roger Bour (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)" (abstract page). Molecular Ecology 12 (6): 1415–1424. doi:10.1046/j.1365-294X.2003.01842.x. PMID 12755871. http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-294X.2003.01842.x. 

• Eric P. Palkovacs, Monique Marschner, Claudio Ciofi, Justin Gerlach & Adalgisa Caccone (2003). "Are the native giant tortoises from the Seychelles really extinct? A genetic perspective based on mtDNA and microsatellite data" (abstract page). Molecular Ecology 12 (6): 1403–1413. doi:10.1046/j.1365-294X.2003.01834.x. PMID 12755870. http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-294X.2003.01834.x. 

External links

• Further information on Seychelles giant tortoises