The saddle-backed Rodrigues giant tortoise (''Cylindraspis vosmaeri)'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

giant 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 ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Testudinidae. The species was

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Rodrigues Rodrigues (french: Île Rodrigues, link=yes ; Creole: ) is a autonomous outer island of the Republic of Mauritius in the Indian Ocean, about east of Mauritius. It is part of the Mascarene Islands, which include Mauritius and Réunion. Rodr ...

. Human exploitation caused the extinction of this species around 1800.

Etymology

The specific name, ''vosmaeri'', is in honor of Dutch naturalist

Arnout Vosmaer Arnout Vosmaer (23 September 1720 – 15 January 1799) was a Dutch naturalist and collection curator. Life Arnout Vosmaer was born in Rotterdam on 23 September 1720 and died in The Hague on 15 January 1799. Very little is known about his personal ...

(1720–1799).

Taxonomy

Both ''Cylindraspis vosmaeri'' and its smaller domed relative, ''

Cylindraspis peltastes The domed Rodrigues giant tortoise (''Cylindraspis peltastes'') is an extinct species of giant tortoise in the family Testudinidae. It was endemic to Rodrigues. It appears to have become extinct around 1800, as a result of human exploitation ...

'', were descended from an ancestral species on Mauritius (an ancestor of '' Cylindraspis inepta''), which colonised Rodrigues by sea many millions of years ago, and then gradually differentiated into the two Rodrigues species.

Description

The saddle-backed Rodrigues giant tortoise was an exceptionally tall species of giant tortoise, with a long, raised neck and an upturned carapace, which gave it a giraffe-like body shape almost similar to that of a

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

dinosaur. It lived by browsing the taller vegetation, while its much smaller relative, the

domed Rodrigues giant tortoise The domed Rodrigues giant tortoise (''Cylindraspis peltastes'') is an extinct species of giant tortoise in the family Testudinidae. It was endemic to Rodrigues. It appears to have become extinct around 1800, as a result of human exploitation ...

, grazed on low vegetation such as fallen leaves and grasses. The saddle-backed Rodrigues giant tortoise was described by early colonists as a docile, gentle browser, with a tendency to gather in large herds, especially in the evening. An early Huguenot settler, in 1707, described the unusual group behaviour of these animals: ''"There's one thing very odd among them; they always place sentinels, at some distance from the troop at the four corners of the camp, to which the sentinels turn their backs, and look with their eyes, as if they were on watch. This we have always observed of them; and this mystery seems the more difficult to be comprehended, for that these creatures are incapable to defend themselves..."'' (Leguat, 1707)

Behaviour and ecology

It has subsequently been discovered that the browsing herds of giant tortoises filled an essential role in the ecosystem of Rodrigues and the regeneration of its forests. Among other roles, the giant tortoises ensured the dispersal and germination of tree seeds, as well as "terraforming" the island by maintaining forest clearings and pools. In recognition of this fact, measures have been undertaken to introduce replacement species, in the form of similar giant tortoises from other parts of the world, to assist in the rebuilding of Rodrigues' devastated environment. The replacement species for the saddle-backed Rodrigues giant tortoise was chosen to be the

Aldabra giant tortoise The Aldabra giant tortoise (''Aldabrachelys gigantea'') is a species of tortoise in the family Testudinidae. The species is endemic to the islands of the Aldabra Atoll in the Seychelles. It is one of the largest tortoises in the world.Pritchar ...

(''Aldabrachelys gigantea'') of the Seychelles, which is roughly similar in size, though very different in body form.

Extinction

At the time of the arrival of human settlers, dense giant tortoise herds of many thousands were reported on Rodrigues. Typically for isolated island species, they were reported to have been friendly, curious, and unafraid of humans. However, in the ensuing years, massive harvesting and exporting for food and the introduction of

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

rapidly exterminated the giant tortoises. Tentative conservation efforts began in the 18th century, with the French Governor Mahé de Labourdonnais attempting to legislate against the "tortoise plundering" of Rodrigues. However, the wholesale slaughter continued. Hundreds of thousands were loaded into ships' holds for food, or to be transported to Mauritius where they were burnt for fat and oil. Due to their unusually thin shells, many died from crushing as they were densely stacked in the holds of ships. In the final years, only smaller specimens were found, lingering in isolated mountainous refuges inland. A surviving giant tortoise was reported on the island in 1795, found at the bottom of a ravine. As late as 1802, there is a mention of survivors reportedly being killed in the large fires used to clear the island's vegetation for agriculture, but it is not clear which one of the two Rodrigues species these were, and which one survived the longest.

References

External links

Rodrigues Saddle-backed Tortoise - The Extinction Website