Mesogastropoda

The term means snails ( Mesogastropoda ) is no longer used taxon within the auger. The Mesogastropoda made ​​within this outdated classification is an order of the class prosobranch ( Prosobranchia ) and form one of the largest groups of species within the auger. Is correspondingly great shape diversity and the diversity of habitats populated. The middle screws are no longer considered monophyletic, ie descended from a common ancestor, considered by the phylogenetic systematics.

The term " means worm " goes back to John Thiele, which assigned this group within the prosobranch due to their morphological features a space between Altschnecken and Neuschnecken. This system was widely accepted for many decades in its fundamentals and was revised by Ponder and Lindberg on phylogenetic basis until 1997. The new system will, however, still under discussion, so that many institutions have recourse to the clarification of important issues by molecular genetic methods to the established system.

Many species of this order are found on beaches or shores of the sea such as the beach snails, but also live in freshwater snails families like the river snails are counted to the center screw. Common to these species, that they have a broad rasp that has more than three, usually even seven teeth per transverse row.

System

• Beach snails ( Littorinidae ) Littorina Great beach screw
• Small beach screw

• Banded Grübchenschnecke

• Hydrobia Common mud snail

• Thin -shelled Rissoa ( Rissoa membranous )

• Turritella Tower snail

• Calyptraea slipper limpet

The system no longer conforms to the current stand