Poecilia wingei

Habitat

In the North-West of the Venezuela, a vast zone lagunaire located in the Sugar state shelters this small fish Ovovivipare, known as of the 19th century under the name of “Guppy of Campoma”.

The Espèce is able of much adaptation and one can find it out of fresh water as out of brackish water, in more or less stagnant water, even frankly polluted, but also in true rivers. The typical habitat is a small slightly brackish river from 1 to 3 m broad and of 20 cm 1 m from depth, with weak current, crossing zones slightly wooded (bushes) or frankly shaded by trees. Water can be green sometimes there because of the presence of unicellular algae. The fish are held preferably on the edges, with the shelter of the current, in sectors being able to be completely deprived of watery plants. They frequently cohabit with other species of petis fish, some being for them the predatory ones, but also with various crustacean small molluscs.

Determination of the species

They is that in 2005, that the scientists Fred NR. Poeser, Michael Kempkes and Isaac J.H. Isbrücker of the zoological Museum of Amsterdam, gave to fish its final name of species “Poecilia wingei”, in homage to Doctor Ojvind Winge (1886-1964), chief of the research laboratory in animal physiology with Carlsberg of 1933 to 1956, famous specialist in Génétique, in particular having worked on the morphological and genetic variations at the guppies and having studied the differences between the guppy of Campoma and the common guppy (Poecilia reticulata).

Within the wild populations of the Poecilia kind, met in Central America, the guppy of Campoma is characterized rather radically by its morphotype quite particular. In particular, the male raises on the back of the body a black reason in the form of comma, more or less marked according to the specimens. Its colors are intense, with reasons metal green and/or blue, and a tail showing a reason in double sword, short and generally asymmetrical. The females are very tall (up to 6 centimetres) and of uniform coloring gray-yellow. The morphology of the Gonopode (sexual organ of the males) is specific to the species, and differs notably from that of Poecilia reticulata. The sexual behavior of the males and the females differs from that of the common guppies. However, the hybridization with P. reticulata is easy in captivity.

These observation were as many indices directing towards a particular species, but not yet sufficient to affirm it.

Fred NR. Poeser and Michael Kempkes were mainly based on the phenomenon of displacement of Caractère to affirm that it was about a species with whole share. At the time of a voyage in the western north of Venezuela, the two scientists found the zones where the fish lived. However, the marked specimens of a reason in comma were only in the Lagune of Campoma and its surroundings, where one met also common guppies ( Poecilia reticulata ). The other varieties without comma met elsewhere in the surroundings of the town of Carúpano, where the common guppies were not. Therefore, the populations which were in sectors where one met at the same time the common guppy were very differently pigmented compared to this one (because of the comma), while the populations which did not live in its presence did not present a comma (but had metal colors). The phenomenon is named in zoology “displacement of character”: two populations of close species tend to resemble each other in a zone where it do not exist together, and contrary, they tend to being different in the zones where they coexist both unit.

Lastly, H.J. Alexander and F. Breden of the Université Simon Fraser of Burnaby to the Canada showed that one was in front of a phenomenon of Spéciation. Speciation is the phenomenon of natural evolution which leads species to be different. P. wingei would be with the whole beginning of this process. By considering populations of a surface of distribution given, it was highlighted that the females did not accept any male, but firstly those which show characteristics corresponding to their “species”. This phenomenon, named sexual Insulation, combined with other factors such as the natural selection in a given environment, led over one long period to establish true a Barrier of species.

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