Mud snails

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Mud snails
European mud snail (Lymnaea stagnalis)

European mud snail ( Lymnaea stagnalis)

Systematics
Trunk : Molluscs (mollusca)
Class : Snails (gastropoda)
Subclass : Heterobranchia
Order : Lung snails (pulmonata)
Subordination : Water lung snails (Basommatophora)
Family : Mud snails
Scientific name
Lymnaeidae
Rafinesque-Schmaltz , 1815

The mud snails (Lymnaeidae) are a family of the lung snails (Pulmonata) and are counted among the water lung snails (Basommatophora). They live exclusively in fresh water and are distributed worldwide.

features

The shells of the mud snails are up to 7 cm in size, mostly conical and right-handed. Some forms can greatly enlarge their opening in the adult stage, or generally have cup-shaped housings (subfamily Lancinae). The housings are usually brownish and z. T. also overgrown. The shell is usually relatively thin. The yellowish to greenish-gray body with dark spots cannot be completely withdrawn into the housing. An operculum is missing. A characteristic feature of the group are the triangular antennae with the eyes at the base. The foot is broad-oval with a rounded rear end.

The animals are hermaphrodites, but have separate sex openings. In copulation, one animal acts as a male and the other as a female, although a mutual exchange of sperm would be possible. But self-fertilization can occur. The eggs are laid in gelatinous strings or clumps on water plants or stones. The clutches contain fewer than 10 up to about 300 eggs. The development takes place via yolk-rich eggs from which finished small animals hatch.

Way of life

A mud snail glides along the surface of the water on the underside of the membrane.

The animals live in slowly flowing or stagnant water. They feed on fresh or rotting plant parts and algae, but carrion is also taken. They are often found moving with their feet up on the surface of the water. The animals come to the surface of the water to breathe and fill their mantle cavity with air through a side, closable opening. They occur worldwide, with the exception of the Antarctic, from the tropics to the arctic regions.

Harmful effect

Individual species are pests on rice plants due to their eating activity when they multiply on a large scale. Still other types are carriers of diseases (e.g. fasciolosis ).

paleontology

Fossil representatives of the mud snails have been known since the Upper Jurassic ( Kimmeridgian or Tithonian , about 150 million years ago).

Systematics

The family is the only family of the superfamily Lymnaeoidea Rafinesque-Schmaltz, 1815 and is currently divided by western authors into the two subfamilies Lancinae and Lymnaeinae. There are also two extinct subfamilies. Russian authors follow a fundamentally different classification. According to more recent molecular genetic studies, even three recent subfamilies can be eliminated. Only a few, mostly central European species have been selected.

literature

  • Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997
  • 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 D., ConchBooks, Hackenheim 2002 ISBN 3-925919-60-0
  • J. Hausser: Cle de determination des gasteropodes de Suisse. Fauna Helvetica, 10: 1–191, Neuchâtel 2005 ISSN  1422-6367
  • Victor Millard: Classification of the Mollusca. A Classification of World Wide Mollusca . Rhine Road, South Africa 1997 ISBN 0-620-21261-6
  • Kruglov, ND & Starobogatov, Ya. I. 1993. Guide to recent molluscs in northern Eurasia. 3. Annotated and illustrated catalog of species of the family Lymnaeidae (Gastropoda Pulmonata Lymnaeiformes) of Palaearctic and adjacent river drainage areas. Part I. Ruthenica 3 (1): 65-92. (145 species)

Web links

Commons : Mud snails (Lymnaeidae)  - Collection of images, videos, and audio files

Individual evidence

  1. ^ MJ Benton (Ed.): The Fossil Record 2. Chapman & Hall, London 1993.
  2. ↑ Ana C. Correa, Juan S. Escobar, Patrick Durand, François Renaud, Patrice David, Philippe Jarne, Jean-Pierre Pointier, Sylvie Hurtrez-Boussès: Bridging gaps in the molecular phylogeny of the Lymnaeidae (Gastropoda: Pulmonata), vectors of Fascioliasis. BMC Evolutionary Biology, 10 (381): 1-12, 2010 PDF
  3. ↑ Maxim V. Vinarski: One, two, or several? How many lymnaeid genera are there? Ruthenica, 23 (1): 41-58, 2013 PDF
  4. ↑ Maxim V. Vinarski, Katrin Schniebs, Peter Glöer, Anna K. Hundsdoerfer: The taxonomic status and phylogenetic relationships of the genus Aenigmomphiscola Kruglov and Starobogatov, 1981 (Gastropoda: Pulmonata: Lymnaeidae). Journal of Natural History, 45 (33-34): 2049-2068, 2011 doi : 10.1080 / 00222933.2011.574800
  5. ↑ Nomenclator Zoologicus - Erinna ( Memento from December 25, 2015 in the Internet Archive )