Spiral staircases
| Spiral staircases | ||||||||||||
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Housing of Epitonium scalare |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Epitoniidae | ||||||||||||
| Berry , 1910 (1812) |
The spiral staircase snails or simply spiral staircases (Epitoniidae) are a species-rich family of mostly small to medium-sized, exclusively marine snails that are distributed worldwide. They feed as carnivores or ectoparasites on sessile cnidarians .
features
The right-hand twisted , thin-walled and fragile, more or less tower-shaped shells of the spiral staircase snails have tightly twisted, not or hardly interconnected, strongly convex whorls that form a high, conical spiral. In many species, particularly pronounced in the genus Epitonium , they have thin, leaf-like axial ribs running over the entire snail shell. In some species, such as the genus Cirsotrema , the housings have not only axial ribs but also spirally running bands. The houses often have a deep navel. The case mouth is round or oval. The round, horny operculum has only a few turns and closes the mouth tightly.
In addition to the radula , the snails have jaws for cutting or biting. The snails eat cnidarians . From large prey or host animals, more or less large pieces are cut out, smaller prey animals are swallowed as a whole. The snails live on their host animals or in the sand or gravel in the area.
The snails are first males and later females. After internal fertilization, the female lays the eggs in capsules, which are covered with sand. The capsules are attached along an elastic thread that is secreted by a gland on the animal's foot. Veliger larvae hatch out of these and go through a longer phase than zooplankton and thus become widespread.
Occurrence and distribution
The Epitoniidae are common in all tropical, subtropical, temperate, arctic and Antarctic seas. They live both in shallow water and at great depths, sometimes up to 6000 meters water depth.
In the North Sea , the family is represented by the common spiral staircase ( Epitonium clathrus ).
Systematics
According to Bouchet and Rocroi (2005), the Epitoniidae family is one of three families in the superfamily Epitonioidea . It has several hundred species in over 30 genera.
literature
- Art Weil, Leonard Brown, Bruce Neville: The Wentletrap Book. Guide to the Recent Epitoniidae of the world . Evolver, Rome 1999.
- Philippe Bouchet & Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005, ISSN 0076-2997
- Winston Ponder & David Lindberg, Towards a phylogeny of gastropod molluscs; an analysis using morphological characters . Zoological Journal of the Linnean Society, 119: 83-265, London 1997, ISSN 0024-4082
- Frank Riedel: Origin and evolution of the "higher" Caenogastropoda . Berliner Geoscientific Abhandlungen, Series E, Volume 32, Berlin 2000, 240 pages, ISBN 3-89582-077-6 .
