Planorbis

Common adjuster screw ( Planorbis planorbis )

Planorbis is a genus of snail from the family of plate screw ( Planorbidae ), which is expected to (probably paraphyletic ) subordination of the water snails ( Basommatophora ) within the lung snails ( Pulmonata ).

Features

The case is almost planispiral, merely sunk to the bottom of something. On the outside of a sharp keel is formed. The animals, however, are tortuous anatomical left. If the housing is appropriately oriented, horizontally with the hole left of center, the spiral is dug up. The animals carry the case tilted sideways with the bottom side up.

Habitat and Distribution

The species of the genus live in slow -moving or stagnant rivers and lakes in the shallow waters of the littoral zones. However, in oxygen-rich waters, they may also in depth ( "surface alien " ), with water-filled lungs cave life, so that two types ( planorbis and carinatus ) were only discovered in 1982 at Lake Lunz by a diver in 7 meters deep, one of whose presence previously knew nothing.

The genus is distributed worldwide.

System

Currently, about five extant species are assigned to the genus, which are divided into two subgenera:

  • Subgenus Planorbis ( Planorbis ) OF Müller, 1778 Planorbis ( Planorbis ) corinna Gray, 1850
  • Keeled plate snail ( Planorbis ( Planorbis ) carinatus OF Müller, 1774)
  • Common adjuster screw ( Planorbis ( Planorbis ) planorbis (Linnaeus, 1758) )
  • Planorbis kahuica Finlay & Laws, 1931
  • Planorbis ( Crassiplanorbis ) presbensis Sturany 1894

In addition there are quite a number of purely fossil forms.

Digital Object Identifier
652626
de