The Pleurodèle de Waltl , Spanish triton or gallipato is a endemic Salamandre in the Iberian peninsula and with the Morocco. It is sometimes confused with the punctuated Triton.

Morphology

It is the greatest triton of Europe: it can reach 30 cm in freedom, and 20 cm in captivity. Its warted skin is brown, its beige belly with black weights. Its long tail represents approximately half its overall length. In the event of attack, it is able to make cover its sides out of its body. This defense system is at the origin of its common English denomination and portuguais some (triton at projecting coasts).

Almost exclusively watery, he prefers calm and clean water. He is equipped with lungs, and goes up regularly on the surface. It is an animal Diurne, credit at temperatures going from 15 to 25 °C. It hibernates between 5 and 10 °C, and also can estiver in the event of lack of water. Its longevity reaches 20 years.

Breeding

Environment

The pleurodèle of Waltl can be installed in a Aquarium of cool water, preferably of at least 80 L for a couple for example. Amphibious animal, it is able to escape in the absence of lid, or to take refuge in the filter of the aquarium. To take care not to use stones or of trachant gravel, the pleurodèle could then be wounded. Lighting, plants, and the hardness water are preferable, but nonessential. It is necessary to filter water and to renew it regularly (approximately 1/4 every two weeks for example). It can be placed in an external basin during the summer.

Cohabitation

The cohabitation with fish is peaceful, but too small animals are likely to become prois for the pleurodèle, and of too large (carp Koï) gober risk the smallest tritons. It is advised to provide shelters to the pleurodèles (tubes, pieces of pots…), to see to prohibit with fish part of the aquarium by a broad netting with meshs.

Food

The food of the pleurodèle is primarily flesh-colored (towards, insects, meat, fish, Crustacés, granulated with Cichlidés…) : it accepts all that with the size of its mouth. The rate/rhythm of the meals passes from 2 times by day for the young people to once all the 2 or 3 days in the adult (15 cm). The pellets are well balanced: the young people appreciate the pellets with cichlidés, the adults the pellets for basic fish. In the event of frozen or alive food, to take care to bring variety to avoid the carrences.

Reproduction

The pleurodèles reproduce rather easily in captivity. It is not necessary to insulate the couple, but it is preferable to isolate the young people. The parades are supported by a water with 15°C approximately. After coupling, the female lays in bunches of the hundreds of eggs which hatch after ten days. The larvae very accept only the alive food of small size (Plancton). They also can nourished the their congeneric ones. From 2cm, the tétards accept a larger food, to see frozen. The méthamorphose takes place around 3 months: the loss of the gills involves risks of drowning. Sexual maturity is reached around 16 month.

Conservation of the species

IUCN class the pleurodèle of Waltl like species Quasi threatened in its red list of 2006. This classification is due to the significant decline of its wild population, due to reduction of its natural habitat and to the appearance of invading species; the species is even close to being classified vulnerable. In 2004, the species was classified minor Préoccupation (LLC). This species is generally threatened by the drainage of its watery habitat, agricultural pollution, the cattle (in North Africa), the Eutrophisation, industrial and domestic pollution, and the development of the infrastructures. It largely disappeared from the Iberian and Moroccan littoral, around the tourist areas and very populated (such Madrid). The introduction of invasive Species of fish and crayfish ( Procambarus clarki ) predatory of the larvae and eggs of this species, contributes to the threat. Mortality on the roads is also a serious danger to certain populations.

Sexual differentiation

Sexual differentiation is initially pulled by the sexual Chromosomes, but can change according to the temperature. The female carries the chromosomes Z and W ( ZW ), the male two copies of chomosome Z ( ZZ ). However so of the larvae ZW are high at a temperature of 32°C with certain stages of their development (stages 42 to 54), they become males.

The Hormones play a big role for sexual differentiation: it is thus possible to change the sex pleurodèles of Waltl by adding hormones or inhibiters of hormones in water.

The Aromatase, an enzyme synthesizing an Estrogen acting like a Steroid, plays a role clée in sexual differentiation as for many Vertébrés not-mammals. It has stronger concentration in the gonades larvae ZW than in those of the larvae ZZ , but not in that of the larvae ZW subjected to a high temérature. This increase takes place towards the end of the stages where the change of sex is possible (stage 52).

Space experiments

The pleurodèle of Waltl was studied in space at the time of with less the 6 missions. The first was led in 1985 to edge of Bion 7. The 10 pleurodèles were accompanied by two rhesus monkeys and 10 rats, in an uninhabited capsule. In 1992, Bion 10 also transported pleurodèles, like Bion 11 in 1996. Research was continued in 1996 by French experiments on Mir (space station) (forwarding Mir Cassiopée), suivient of studies in 1998 (forwarding Mir PEGASE) and in 1999 (forwarding Mir Perseus). Foton-m2 lodged also pleurodèles in 2005.

The pleurodèles were selected for their organization lending itself to the study microphone-gravity well. The female is indeed able to preserve sperm in its cesspool for 5 months, allowing an insemination on Earth then a fertilization in space by hormonal stimulation. Moreover their slow development allows to observe the key stages of the Ontogenèse, of the Ovocyte to the larvae.

Studies related on the capacity of Régénération of the pleurodèles (faster in space, up to 2 times in the first stages), like to the stages of development and the reproduction in space.

On Earth, the effects of the hypergravity (until 3G) on the fertility of the pleurodèles of Waltl were also studied, as on the fertility of the pleurodèles born in the space of return to earth (they were fertile, and without particular problem).

Other Amphibians were sent in the space, of which the pleurodèles Lissotriton vulgaris and Cynops pyrrhogaster , the xénope of the Cape, the tree frog Hyla japonica , like several frogs of the kind Rana  : Rana pipiens , Rana calestiana and Rana temporaria .

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