Overlapping Tortoise

The overlapping Tortoise or Tortue with scale ( Eretmochelys imbricata ) is one of the seven current species of marine tortoises and the only one of the kind Eretmochelys . It is characterized by several anatomical characters and ecological single, it acts in particular of only the Reptile known Spongivore.

It is also called reel or carette locally, in particular with the the Antilles or the Meeting, these names lending however to confusion with the tortoise caouanne (Caretta caretta) .

She saw near the coasts in the whole of the tropical Mer S . Considered and a long time required for the higher quality of sound scale, it is because of that one of the species of turtles the most threatened of extinction.

Description

Appearance

The aspect of this species is rather similar to that of the other marine tortoises. Its osseous carapace, without continuous and very coloured hull is rather flattened. Its legs are transformed into oars. It is however easily distinguishable by its thick scales recovering the backing, posed like the tiles of a roof, by its long nozzle, narrow and hooked and by both claw S laid out with a few centimetres one of the other on outside with semi-fins. The backing of the carapace is made of five vertebral plates and four pairs the costal ones. Moreover, 11 pairs of scales known as marginal and a pair of scales post-power stations are present on the edge of the carapace.

The backing of the carapace is of a color brown orange. This coloring is an irregular combination of scratches clear and sunk with yellow or red spots. The drill plate is yellow, the post-anal scales are of the same color with black spots. The fins are brown on the top and yellows below. Lastly, its small head is brown with four scales préfrontales. Its Mâchoire S is yellow, the lower having a form of V.

The youthful ones are black, except on the edge of carapace, which is yellow. This one is in form of Cœur to the birth, then becomes Ovale while growing. Moreover, the serration formed by the marginal scales grows blurred with the age.

The males are characterized by a clearer pigmentation and, as for the other species of tortoises, a concave drill plate, longer claws and a thicker tail.

Characteristics

The overlapping Tortoise measures between 60 and 100 centimetres and weighs between 43 and 75 kilograms, the largest specimen found making 127 kilograms. The eggs measure between 30 and 45 millimetres and weigh between 20 and 31,6 grams, is more than 81 minutes.

The sexual Maturité is reached in this tortoise after ten years, even probably around twenty years and can reproduce at least during ten years. It is thus described as species with late maturity. Its Life expectancy is not known.

Behavior and food

The conditions of observation being difficult, the food of the tortoises in pelagic zone is not very well-known; it is thought that they must nourish primarily jellyfish S. In benthic zone , and more particularly in the coral reefs, they consume especially sponges. In the the Caribbean, these last constitute 70 with 95 besides; % of their food mode and, like much of spongivores, they more specifically consume only precise species of the class of the Demospongiae , and those pertaining to the orders Astrophorida , Spirophorida and Hadromerida .

Certain consumed sponges are besides known to be very toxic for other organizations. It is the case in particular of Aaptos aaptos , Chondrilla nucula , Tethya actinia , Spheciospongia vesparium and Suberites domuncula . The overlapping tortoises particularly seem to appreciate the most siliceous sponges like those of the kinds Ancorina , Geodia (whose Geodia gibberosa but this variation can vary between nine months and 10 years. The reproduction can even be held several times the same year, at fifteen days of interval. Moreover, made particular, the female stores reserves of Spermatozoïde S. It can thus reproduce during several years without having contact with a male.

One could determine that for each site, the tortoises had a certain genetic homogeneity, which tends to prove that the females come to lay at the place where they were born. Each one unloads on the beach and digs a deep nest of at least 10 centimetres and 90 centimetres to the plus^,. Few of other reliable data are available.

The overlapping tortoise hybrid easily with other marine tortoises, such as the Caouanne S. Certains hybrids found with the Brazil or in Florida are viable and fertile because they exist since at least two générations^,. An hybrid of green Tortue was also discovered with the Surinam.

The determination of the sex in the overlapping tortoises is very hazardous. The sexual characters are not always outside visible. Secondary sexual characters (as for the other tortoises: the width of the tail, the claws or the shape of the drill plate) are not always determining. Only the blood analysis is a reliable method. The tortoise is Ovipare, and as for the other tortoises, the temperature of incubation determines the sex of the Embryon S in eggs. The sex ratio would lie between three and four females for a male. Once adult, its only predatory is the shark and especially the man, but its rate of survival is all the same very high (95% for an adult female). The tortoises always regain their usual habitats between the periods of migration. Thus, when the overlapping tortoises disappear from a zone, there is no repopulation by other individuals and disappearance is final.

Migration

It was wrongly thought, until recently, who the overlapping tortoise was less migrating that the other species of marine tortoises. Studies using the satellite telemetry showed that this species travels on thousands of kilometers. It is probable that the overlapping tortoises feed and multiply in completely different zones.

Distribution

The Atlantic

It is estimated that to the maximum: 5000 overlapping tortoises lay annually in the the Caribbean and 600 with the Brésil, the Surinam and in French Guiana; largest remaining population niche with the Mexico. One does not have data on all the countries such as for example the Guyana, Cuba, the Florida, Grenade, the Guatemala, Montserrat, Trinity-and-Tobago, the Venezuela and the Cayman Islands. However, generally, much of studies on these tortoises are carried out in the area. It is considered that the populations are exhausted there or practically exhausted even if their number in the Péninsule of Yucatan to the Mexico and Isla Mona is in increase. The population of Antigua (Jumby Bay) and in the Îles San Juan (Buck Island) is regarded as stationary. This species is met in this area, of the north of the United States i.e. until Long Island Sound and Massachusetts until in Argentine. In the west, it is observed Manche with the Cape of Good Hope. No observation of layings of overlapping tortoises took place in the Mediterranean and the reports/ratios documented on observations at sea are almost non-existent.

The distribution on the West African coast is less known than in the Caribbean. It is known that in the Années 1800, the Golfe of Guinea and the islands of Sao Divide into volumes-and-Principle were important sites of laying and transformation of the scales. We do not have precise statistical data, but there would remain a few hundreds of layings per annum. In 1996, scales were always on sale to the tourists in this area.

Indian Ocean

Thanks to the shape of the scales, six classes of overlapping tortoises are identifiable in this area. Thus, the populations of overlapping tortoises laying in East Africa, Asia and on the majority of the islands have known a considerable decline for hundred years. Certain areas do not have layers any more. Whereas they had been described like extremely many formerly, there does not exist any more but: 6000 with: 7000 layers per annum by not counting the Indonesia and the Australia in 1999. Only the populations of the Seychelles are in increase;

the islands Daymaniyat with Oman;
Shitvar in Iran, but the data on this site are currently compartmental or non-existent;
French Guiana;
Strait of Torres and Ground of Arnhem in Australia;
Peninsula of Yucatan, Mexico.

Inventory position

In 2007, there does not exist any more in the world but five great sites of annual gathering of more than thousand tortoises which are located at the Seychelles, to the Mexico and two in the north of the Australia and as being in critical danger of extinction since 1996.

The efforts of protection of the Années 1980 bore their fruits only in rare places where a stagnation is noted. However, not positive, a light increase in manpower was observed with the Yucatán, Isla Mona and on the island Cousin.

The relative evolutionary independent groups are described below by phylogeny according to Hirayama, 1997,1998, Lapparent de Broin, 2000, and Parham, 2005:

Denomination

One calls it in Guadeloupe the karet . The origin of the word " Caret" is known little about, but it dates from the 16th century and could be a loan with the Caribbean languages via the Spanish . It is also called “tortoise with nozzle of falcon” (as in English Hawksbill turtle ) because of his hooked nozzle. But in French, it is known as “overlapping” and in Latin “ imbricata ” because the back plates of its backing overlap.

The overlapping tortoise was described at the origin by Carl von Linné like Testudo imbricata , in 1766. At the beginning of the 19th century, the systematic one is refined, one recognizes with the marine tortoises of the common characteristics and one gathers them within Taxon S commun runs. A new kind Eretmochelys (of the Greek : eretmo , oar and chelys , tortoise) is proposed by the Austrian zoologist Leopold Fitzinger in 1843.

This species of tortoise is especially eaten with the Japan and in China even if the meat, and especially the skin, frequently proved toxic. This practice, including for the imbricated tortoise, is attested since at least the O C. The use of the scale of overlapping tortoise is attested between the China and the ancient Rome. The scale present of the hot colors and, in the skilful hands of craftsmen, it can be welded, moulded, cut out and carved.

The Japanese call the scales of tortoise bekko . In 1983, the only known stable populations were with the the Middle East and the North-East of the Australia. In 1986, then in 1988, the UICN announces an aggravation of the situation. The Japan continuous to import approximately 1985 with 1990 2,7 tons on average until in 1992 where it imports 175 kilograms of them, the Indonesia, Haiti, Cuba do not respect the recommendations of QUOTE. The very rare surviving tortoises in the Atlantic, as with Sao Tome, continue to be fished and their carapaces sold with the tourists.

However according to QUOTE

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