Water snails

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Water snails
Ramshorn snail

Ramshorn snail

Systematics
Trunk : Molluscs (mollusca)
Class : Snails (gastropoda)
Subclass : Orthogastropoda
Superordinate : Heterobranchia
Order : Lung snails (pulmonata)
Subordination : Water snails
Scientific name
Basommatophora
Keferstein , 1864

The water lung snails (Basommatophora), more precisely water lung snails i. w. S. , are traditionally considered to be subordinate to the pulmonary snails . They occur in fresh water and in the marine area. They have developed a lungs that use either air or sometimes water for breathing.

Various recent studies have shown that water snails i. w. S. are not a natural taxon but represent a paraphyletic group because they do not contain all of the descendants of their last common ancestor . They are therefore referred to as a group in systematic representations or written in quotation marks ("Basommatophora", "Water lung snails iwS"). However, all true native representatives belong to a monophyletic subgroup, the Hygrophila ( water pulmonary snails in the narrow sense or freshwater pulmonary snails ; see under systematics).

features

This subordination of mainly air-breathing lung snails is characterized by a pair of antennae, at the base of which are the eyes. Hence the name Basommatophora, from the Greek βάσις (basis) = basis, ὄμμα (omma) = eye and φέρω (phero) = I wear. Some forms take up oxygen through the body surface or through the body surface and "lungs". With the exception of the Amphibolidae family, they do not have a shell lid ( operculum ). The housings vary from trocho- to planispiral. Cup-shaped shells are also found (Siphonariidae, pond limpets, some potted snails).

Habitat and Distribution

The water snails i. w. S. occur worldwide. They live on the one hand in fresh water (especially the Hygrophila), on the other hand in the littoral area of the seas. In Central Europe there are four families, all of which belong to the Hygrophila: Mud snails (Lymnaeidae), pond limpets (Acroloxidae), pancake snails (Planorbidae) and bladder snails (Physidae). Those genera that used to be run as an independent family "Ancylidae" are now predominantly associated with the poppy snails.

The representatives of the Siphonariidae colonized the sea secondarily. Amphibola crenata (Gmelin, 1791) lives in the splash water area of ​​the intertidal zone or in the marsh area; it can be described as a semi-terrestrial species and is able to survive buried in the mud even during longer dry phases.

Systematics

The systematic allocation of the individual families and genera is still in flux and is only slowly stabilizing. The following list follows Jeffrey (2001) and in particular the subdivision made by Bouchet & Rocroi (2005) of the "water snails in the broader sense" into six superfamilies and nine families, one of which is only described in fossil form. This provisional large-scale division is largely in line with more recent molecular genetic findings.

The clear separation and classification of the superfamilies of the "Amphiboloidea" and the "Siphonarioidea" in monophyletic taxa is not yet possible, which is why they are provisionally placed in front of the Hygrophila. A division into three families has recently been proposed for the family of the Amphibolidae, the Amphibolidae, the Phallomedusidae and the Maningrididae. However, this is also to be regarded as provisional, as not all genera and species could yet be assigned, which is why the following list refrains from this classification.

The classification of the † Acroreiidae will probably remain fundamentally uncertain as a result of the lack of characteristics of the fossils preserved, as long as significantly better fossil finds are not known.

  • Group "Basommatophora" ("Water Lung Snails iwS")

a) the following two superfamilies are provisionally classified here and possibly represent paraphyletic or polyphyletic groups

b) the following four superfamilies form the monophyletic taxon Hygrophila

Bouchet & Rocroi (2005) dispense with category designations above the superfamily in their classification and leave open how the Hygrophila are to be classified. However, according to taxonomic usage, the Hygrophila are most likely to be equated with a partial order (infraordo). In the English-language literature, the Hygrophila are also referred to as "Higher Basommatophora".

Individual evidence

  1. ↑ Peter Glöer: The animal world of Germany. Mollusca I Freshwater gastropods of Northern and Central Europe Key to identification, way of life, distribution. 2. rework. Ed., 327 pages, ConchBooks, Hackenheim 2002 ISBN 3-925919-60-0
  2. ↑ Paul Jeffery: Supra Generic classification of class Gastropoda . The Natural History Museum, London. 2001
  3. ^ Philippe Bouchet, Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997
  4. ↑ Klussmann-Kolb, A. , Dinapoli, A., Kuhn, K., Streit, B., Albrecht, C .: From sea to land and beyond - New insights into the evolution of euthyneuran Gastropoda (Mollusca). BMC Evolutionary Biology 2008, 8:57. doi : 10.1186 / 1471-2148-8-57 (2008)
  5. ^ RE Golding, WF Ponder, M. Byrne: Taxonomy and anatomy of Amphiboloidea (Gastropoda: Heterobranchia: Archaeopulmonata). Zootaxa 1476: 1-50 (2007)

literature

  • Victor Millard: Classification of the Mollusca. A Classification of World Wide Mollusca. Rhine Road, South Africa 1997, ISBN 0-620-21261-6 .
  • Winston Ponder & David Lindberg, Towards a phylogeny of gastropod molluscs; an analysis using morphological characters. Zoological Journal of the Linnean Society, 119, London 1997, ISSN  0024-4082 , pp. 83-265.

Web links

Commons : Panpulmonata (Panpulmonata)  - Collection of images, videos, and audio files