Sea snails

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Sea snails
Marstonia comalensis

Marstonia comalensis

Systematics
Superordinate : Caenogastropoda
Order : Sorbeoconcha
Subordination : Hypsogastropoda
Partial order : Littorinimorpha
Superfamily : Littorinoidea
Family : Sea snails
Scientific name
Hydrobiidae
Stimpson , 1865

The hydrobiidae (Hydrobiidae), also watt screw , sadleriana or bithyniidae are a diverse family from the group of Caenogastropoda . The very small to small snails are found worldwide mainly in fresh water , but also in brackish water and in some cases in sea ​​water .

features

Water snails have small, conical and smooth, right-hand winding shells with a mostly oval, always whole-rimmed mouth. The snail shells of adult snails have 2 to 8 whorls and are no longer than 8 mm, but the house can always accommodate the whole, small snail. The horny cover ( operculum ) is spiral with a few turns.

The snails have a long, two-part snout and two thread-like, pointed or blunt antennae, at the base of which are the eyes. The hem of the coat can be simple or it can be studded with extensions. The foot consists of a front and a rear half. The mucous gland is centrally located on the front edge of the foot. The head, foot, mantle and viscera are colored pale gray to dark purple or black due to melanin .

The mantle cavity contains a gill almost in its entire length , which consists of 10 to 200 triangular filaments. The osphradium is usually small.

The radula is of the Taenioglossa type with more than fifty rows of teeth. The central tooth is trapezoidal in shape and the posterior teeth have a few to many cusps, the marginal teeth usually have many cusps.

The sea snails are mostly separate sexes, with the male mating with the female with his penis . The females lay their eggs in individual egg capsules, often on aquatic plants, but there can also be ovoviviparia . In this case there is a direct development, but in most species ready-made snails hatch. In some species there is a development via Veliger larvae.

Since the shells of the sea snail have few species-specific characteristics and at the same time many species are very variable, the characteristics of the operculum, the radula and the penis must be used for species descriptions and species identification.

Distribution and way of life

Most sea snail species live in fresh water, for example in lakes or rivers, while other species occur in brackish water. A few species live in salt water, especially on sandy or muddy subsoil between algae or in seagrass meadows .

The snails live on algae and detritus .

Some types

In the North Sea and the Baltic Sea, the family is represented by the common watt snail or smooth watt snail ( Hydrobia ulvae ), the bellied watt snail ( Ecrobia ventrosa ), the pointed watt snail ( Hydrobia acuta ) and the overlooked watt snail ( Hydrobia neglecta ). Introduced from New Zealand in the North Sea is the New Zealand mud snail ( Potamopyrgus antipodarum ), and frequent in the Black Sea stone adhesive ( Lithoglyphus naticoides ) has passed through the waterways also to Central Europe.

Systematics

According to Bouchet and Rocroi (2005), the Hydrobiidae family is one of 19 families in the superfamily Rissooidea . The Hydrobiidae family currently includes over 160 genera:

supporting documents

literature

  • Bernhard Grzimek (ed.): Grzimeks animal life. Encyclopedia of the Animal Kingdom in 13 volumes. Volume 3: molluscs and echinoderms. Unchanged reprint of the dtv edition from 1979/80. Bechtermünz-Weltbildverlag, Augsburg, 2000 ISBN 3-8289-1603-1
  • Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005 ISSN  0076-2997

Individual evidence

  1. Jürgen H. Jungbluth, German Malakozoological Society: German names for native snails and mussels (Gastropoda et Bivalvia) (mollbase.de). Version dated January 15, 2002.
  2. Doris Freudig (Ed.): Lexicon of Biology . Herder Verlag, Freiburg 2004.
  3. Robert Nordsieck: Dwarf snails (Hydrobiidae) on Weichtiere.at
  4. ^ Václav Pfleger: Mollusks. 192 pp., Artia-Verlag, Prague 1984 (p. 50).
  5. World Wide Mollusc Species Database by Bagni Liggia
  6. ^ World Register of Marine Species , Hydrobiidae Stimpson, 1865
  7. a b c Winston F. Ponder, GA Clark, AC Miller, A Toluzzi: On a major radiation of freshwater snails in Tasmania and eastern Victoria: a preliminary overview of the Beddomeia group (Mollusca: Gastropoda: Hydrobiidae). Invertebrate Taxonomy, 7 (3) 501-750, 1993 abstract

annotation

  1. According to Jürgen H. Jungbluth, mollbase.de , the name Watt snail only refers to a part of the sea snails.

Web links

Commons : Sea snails (Hydrobiidae)  - Collection of images, videos, and audio files