Planorbarius corneus

Planorbarius corneus

The horn snail ( Planorbarius corneus ) is a representative of the water snails ( Basommatophora ) and the family of the plate screw ( Planorbidae ) expected; it is not to be confused with the same family belonging to the genus Posthörnchen ( Gyraulus ).

Features

It has a flat trochospirales, linksgewundenes housing having a diameter of up to four centimeters. It consists of 4.5 to 5 turns and is firm and thick-walled. It has growth lines and occasionally visible from outside. The coat is dark brown to reddish black.

As the only European species of snails as it has blood pigment hemoglobin and therefore red-colored blood. Due to the high oxygen affinity of hemoglobin, the ram's horn snail can survive even in very low-oxygen waters. Although it is a lung worm, breathing takes place only to a very small extent by the absorption of atmospheric air. It outweighs the gas exchange through the skin and into the mantle cavity ( " lung" ), this secondary gill (also Pseudokieme or Hilfskieme called ). This secondary gill - a rag -like extension - projects in active animals often out of the mantle cavity.

Sometimes, there are albino animals. This lacks the dark pigment melanin, so that the corresponding screw due to the hemoglobin have a red body.

Reproduction

Like most water snails is also the horn snail a hermaphrodite and lays its eggs in the summer. The water temperature must be at least 12 ° betragen.Diese snail fertilizes itself Eggs are laid as flat, jelly-like lumps on leaf undersides of aquatic plants. The service life is up to 3 years.

Lifestyle and dissemination

The horn snail is an omnivore. They mainly feed on algae, dead plants and carrion. Only when food shortage occurs, they will also eat live plants. The horn snail is diurnal and lives in fresh water, preferably in standing and slowly flowing waters. The wintering horn snail occurs in the mud. Their presence extends across the whole of Europe, in the East as far away as Siberia. In Northern Europe, the occurrence extends to southern Norway, southern Sweden and Finland.

Planorbarius corneus

Aquatics and cultivated forms

The horn snail has become an integral part of the aquarium. Commercially also several color forms, especially blue and pink Ramshorn snails are available.

Endangering

The species is listed as endangered in Austria and Switzerland.

Swell