Planorbis planorbis


Planorbis planorbis is a species of air-breathing freshwater snail, an aquatic gastropod mollusk in the family Planorbidae, the ram's horn snails.

Taxonomy

Planorbis planorbis was originally described as Helix planorbis by Carl Linnaeus in Systema Naturae in 1758.

Distribution

Planorbis planorbis can be found across much of Europe and Northern Africa. It is considered invasive in many European countries, including:
This species, like all planorbids, has a sinistral shell. The width of the shell is 15 – 20 mm. The keel on the periphery of the shell is near the edge closest to the spire side, which is carried downwards in life.

Ecology

The habitat of this species is shallow standing and slowly running freshwaters on a mud substrate, also ponds and temporarily drying flood waters, up to depth. It seems to prefer habitats with large amounts of vegetation and high pH. Planorbis planorbis does not tolerate intensive water movements but is tolerant to eutrophic conditions.
Between 1–500 individuals per square meter may be found per water source.

Reproduction

Planorbis planorbis has 2 reproductive cycles per year, which are tied to the seasons. In the northern hemisphere, spawning takes place in February and during the summer–early autumn. Juveniles likely grow fast enough to participate in the next spawning season. After reproduction, the snails may survive through the following winter.