Tortoise lute

The tortoise lute ( Dermochelys coriacea , Blainv., 1816) is largest of all the current Espèce S of marine tortoises and tortoise S in general.

It does not have a true carapace, but its back is protected by an armor from thick and careened skin. It is the only contemporary representative of the group of the Dermochelyoidae , the Clade of the tortoises with armoured back, also known by various fossil species, of which certain giants like the Archelon.

The tortoise lute attends all the Océan S of planet, but its survival is seriously threatened by the poaching, the fishing nets, the pollution and the urbanization of the littoral. It is reproduced on the list of UICN of the species in way of disappearance and is the subject of conventions and international programs of protection and conservation.

Description

Morphology

The particular anatomy of the tortoise lute characterizes the family of the Dermochelyidae from of which all the other species disappeared since the tertiary era.

The most remarkable feature is the visible absence of hard carapace as at the majority of the other tortoises. In the tortoise lute, the osseous structure of the carapace is reduced to small ossicles in the imbricated star shape, inserted in a conjunctive and cartilagineux fabric thick. Largest of these ossicles are tubers and laid out in lines. These lines, visible under the skin, form corrugated peaks called hulls which spin head towards the tail of the animal giving him an aspect profiled like the hulls of the hull of a Bateau. The back of the animal presents seven hulls: that of the medium is the “vertebral hull”, the six others are the “side hulls”. On the belly, the drill plate has only three little marked hulls.

This deeply transformed carapace is not attached, not made single at the species of still alive tortoises, with the Spinal column and with the coasts but is separated by from it a fat layer. External side it is completely deprived of any cover of scales. The protection of the back on the other hand is ensured by a marked thickening of the skin, which forms a smooth pseudo-carapace thus having the aspect of the Cuir.

The backing of the tortoise lute can weigh up to 500 kilograms and measure up to 1 meter 80)

Like the other marine tortoises, the tortoise lute is unable to fold up itself inside its carapace.

But it is also a single tortoise by many aspects:

Its fins (or oars) are deprived of griffes ; its former fins are moreover very long compared to those of the other turtles.
the head is very large, which contrasts with a little developed muzzle. On the higher nozzle, one can observe a very marked median point surrounded by two great notches. The interior of the mouth is occupied by a multitude of cones, used as well for oxygenation.

The tortoise lute is excellent plunger since scientists raised several observations of tortoises lute up to 1300 meters of depth for some 4938 seconds divings (either more than 80 min).

Adult, it measures up to 2 meters length for a varying weight of 450 kilograms to a record observed of 950 kilograms. It is thus largest and heaviest of the alive tortoises. It was however exceeded by old species, known with the state of fossils, in particular the Archelon ( Archelon ischyros ). It is this however less long and less door that the marine crocodile ( Crocodylus porosus ).

Colors

The Couleur of the Peau of the animal is of a very dark blue. It is brilliant and smooth, which gives him the aspect of leather. The hulls of the backing are underlined by an explanation of the skin. All its body is strewn with small points blanchâtres. The cranium of the animal presents a spot, of white color with dew, corresponding to a Chanfrein. This spot has a single configuration for each tortoise lute, and the scientists think that it could be used to detect the light or to locate in space that of water where it evolves/moves. Its fins also help it to store the heat. They function like exchangers of heat to counter-current. According to certain theories, its pseudo-carapace could create its own heat. But this assumption is discussed, owing to the fact that the reptiles, animals with cold blood, are supposed being Poïkilotherme S.

Distribution

The tortoise lute is observable in all the oceans of the world, under latitudes observed at least with more 60° in north and 27° in the south , i.e. until the Arctic Circle. Precise studies are carried out to know their migrations precisely.

Like the majority of the marine tortoises, she ventures on the dry land to only lay.

Many places of layings formerly attended by the tortoises lute are not it almost more or any more. They leave each year tropical water for polar water while following the Gulf Stream. The tortoise lute can remain up to eighty minutes in diving, partly thanks to the extraction of the oxygen of water using long Papille S located in its throat and at the oxygen recovery dissolved in some of its fabrics, but it can also nourish Salpe S, of Poisson S, Crustacé S, Calmar S, sea urchin S and even of certain plants, of which Algue S (especially consumed by the young specimens). It can consume daily a quantity of jellyfishes equal to its own weight, that is to say to 50 individuals of large jellyfish Rhizostoma pulmo . The tortoise lute thus has a crucial role in ecological but so economic balance because of its food.

The tortoises not having teeth and the jellyfishes being difficult to shred, the scientists wondered how the tortoises lute could feed with these animals. It was discovered that the esophagus of the tortoise lute, papered spines, had as a function the cutting-up of the preys.

Several studies of followed by satellite to know to them migration were carried out in particular by the CNRS and the French polar Institut - Paul Emile Victor which equipped with the tortoises lute of beacons Argos.

Reproduction

As the tortoises lute only approach the coasts to lay and prefer deep seas, they are described as Pélagique S:

the rise: the female joined the top of the beach, with the edge of the vegetation, in approximately 10 minutes.
sweeping: it clears sand with its legs during fifteen minutes.
the digging: it digs a hole up to 80 centimetres of depth with its legs back; the operation takes approximately 25 minutes.
the laying: this stage is accompanied by raucous breathings and is carried out by salvos; it lasts a score of minutes; the presence of the man cannot any more disturb it; the eyes of the animal secrete a gelatinous substance, a priori , to evacuate the salt accumulated by its organization because of its mode of food.
stopping: the posterior legs bring back sand on eggs and the posterior fins pack it during small ten minutes.
camouflage: during 20 minutes, the tortoise swivels on itself to hide the traces of its passage.
the return to water: sometimes direct, sometimes indirect, the tortoise lute can carry out loops before its departure.

. Between 26 and 30°C, it is traditional incubation, producing a mixture of males and females. Above 30°C, the tortoises will be only females.

With the blossoming, the specimen measures from 7 to 8 centimetres length. It has oversize former fins). But, the eggs are also directly threatened by the insects and, in French Guiana in particular, by the Courtilière. Once arrived at water, the young tortoises lute are not yet in safety, they become the preys of the Pieuvre S and large fish.

But, if the tortoise lute is a species in the process of disappearance, it is mainly because of the man. The first reason is the water pollution. As example, the tortoise lute confuses the bags in Polyéthylène rejected into the sea with jellyfishes, eats them and cannot the régurgiter, which causes a gastric or intestinal occlusion to them. It is the greatest cause of mortality of the animal. The hunting of the animal in itself is sometimes even noted. To the Togo, in particular, féticheurs reduce the carapace of the powder animal, mingle it with honey and make use of it like remedy against the infantile syncope S. Grease is used against the Rhumatisme S. the carapaces, in addition, are also sometimes used in local traditional art (a hundred of them is exposed to the Museum of Geology of the University of Togo). In certain countries, the females are killed and their skin is transformed into tourist jewels and other memories.

See also: Contenu=Voir also: [[Tortoise marine#Prédateurs]], [[marine Tortoise: Predatory]]

Protection

There would remain nothing any more but 100.000 tortoises lute approximately in the world. And as of many populations of tortoises lute have been in Net decline for several years and than the number of places of laying fell much, the tortoise lute is registered on the red Liste of the UICN as in “critical danger of extinction”.

It is also a protected space by many international conventions, in particular by its inscription with the Annexe I of QUOTE.

Measures were taken for better studying the animal and thus, to protect it, like the installation of follow-ups by Télémétrie and beacons Argos. Moreover, the beach where the greatest number of laying in Africa takes place, with the Gabon, is officially protected following creation from the National park Mayumba. WWF puts forward four principal measures of protection of the tortoise lute to reduce the accidental catches of the animal in the nets of the fishermen. The researchers identified important points of regrouping of the tortoises and try to reduce the activity of fishing in these places.

Classification and denomination

Systematic

The Luth tortoise forms part about the Testudines and of the family of the Dermochelyidae. One thinks that the differentiation which was going to give rise to the line of the Dermochelyidae and the Cheloniidae is made, of the beginning of marine colonization by the tortoises with the Crétacé between 100 and 150 My.

The relative evolutionary independent groups are described below by phylogeny according to Hirayama (1997, 1998), Elliott, Irby and Hutchinson (1997), Moody (1997), Hooks (1998) and Lapparent de Broin (2000):

- O Chelonioidea |--O (...) Cheloniidae , other marine tortoises `--O Dermochelyoidea (Gray, 1825) |--O † Thalassemyidae , at least five let us tax `--O Dermochelyoinea sensu Hirayama 1998 |--O Dermochelyidae (Gray, 1825) | `--O | |--O † Cardiochelys (at least two let us tax) | `--O | |--O † Protosphargis | `--O | |--O † Eosphargis (at least 2 let us tax) | `--O Thalassochelys (Bergounioux, 1956) | |--O † Psephophorus (at least 4 let us tax) | |--O † Mesodermochelys | `--O Dermochelys (Blainville, 1816) “--O † Protostegidae (Cope, 1872), at least about fifteen let us tax of which the Archelon
Legend: † = extinct

The taxonomy of this tortoise followed the evolution of knowledge on the phylogenetic one of the tortoises, which defined gradually tax more precise. This species thus was found, in turn, classified in the Testudines , Testudinata and Chelonia . Certain authors even classified it under order created for the occasion of the Athecae . But it was shown that they were close to the other tortoises marine and placed in the same super-family.

Vernacular names

The tortoise lute bears names different according to the countries from the world but the majority refer to the particular form of its carapace. If one compares, in the French language and the Italian language ( liuto ), the shape of the tortoise to that of a Luth, it is probably because of its very developed spur supercodal.

In English ( leatherback sea turtle ) and in German ( Lederschildkröten ), it is the leather aspect which its skin has which gave him its vernacular names.

Into Malayan, it is its form, again, which is worth to him its name of penyu belimbing , that is to say in French: “tortoise carambola”.

One finds multiple denominations of the tortoise lute in the language Créole Guianese :

toti cui (tortoise leather) ;
toti fran (frank tortoise) ;
toti cerkeil (tortoise coffin).

In kali' Na, language of the Amerindians living close to the great sites of layings in French Guiana and in Suriname, the name of the tortoise lute is kawana . This name could be borrowed in French to indicate the Caouanne, another tortoise marinades Caretta caretta .

Appearances in the historical and popular culture

The particular shape of the carapace of the Luth tortoise influenced the popular art of certain civilizations. Thus, the Seri Indians, in California, think that the world had begun its development on the back of a tortoise lute giantess. By habit, they paint the skeletons of the dead found tortoises lute.

The tortoise lute is an animal emblematic among the marine tortoises and its image is often used:

the commemorative Timbre French more sold 2002 is that representing it (0,41 €); it ran out to 19,95 million specimens. It is emitted within the framework of the annual series Nature of France and is drawn by Christian Broutin.
It makes an appearance in the video game Sea Life Park Empire (to free) and in the Add one of the Video game Zoo Tycoon 2: Navy Handled (it belongs to the 20 new animals added in this supplement, among which there are only two tortoises, the other being the green Tortue).
In the series Sherlock Yak Zoo-Detective of Michel Amelin (Milan editions), intended for the children, the hero inquires into murders made on the animals emblématiques of the zoo (tiger, penguin…). Thus, one of its adventures names Which electrocuted the tortoise lute? .

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