Triton snails

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Triton snails
An Atlantic triton snail (Charonia variegata) eats a starfish

An Atlantic triton snail ( Charonia variegata ) eats a starfish

Systematics
Superordinate : Caenogastropoda
Order : Sorbeoconcha
Subordination : Hypsogastropoda
Partial order : Littorinimorpha
Superfamily : Cassoidea
Family : Triton snails
Scientific name
Ranellidae
Gray , 1854
Cymatium lotorium

The Triton snails (Ranellidae) are a family of mostly quite large snails that live exclusively in the sea . All representatives of the family are predators who live in tropical and subtropical seas.

features

The casings are right-hand wound and rolled up trochospirally. The mouth is usually oval with folded edges. The opening can be narrowed and modified by transverse ribs and "teeth" (protrusions). Often the lower end is pulled into a siphon channel. Some of the cases are heavily ornamented. The adult size ranges from 1.5 to 50 cm. The well developed foot is very muscular. The head has no or only a short snout. The antenna bases are strongly thickened. Therefore, the eyes on the antennae are relatively high above the actual head. The housing opening can be closed using an operculum . As far as is known, the family is of separate sex. The ontogenetic development is not uniform within the family. While the development usually takes place via a plankton-eating larva, nourishing eggs also occur, i. H. the embryo eats other, mostly unfertilized eggs in the clutch and hatches out of the protective clutch shell as a finished, small animal.

Way of life

Triton snails predatory feed on echinoderms , sea ​​squirts , mussels and other snails. They live in all subtropical and tropical seas, mostly in the tidal range , in coral reefs , on rocky coasts and in sandy shallow water. The prey is mostly paralyzed by the secretions of the large salivary glands and z. T. probably also pre-digested. The prey is then swallowed whole or chopped up with the radula, depending on its size.

The preferred prey differs within the Ranellidae family: the conch horns (genus Charonia ) mainly eat echinoderms. Cabestana spengleri and Ranella australasia eat almost exclusively sea squirts, Septa parthenopium both mussels and sea squirts. Various representatives of the genus Cymatium , on the other hand, eat shell-bearing molluscs, depending on the species more like mussels or snails. Some Cymatium species, especially Cymatium muricinum , can become a problem in mussel farming.

Systematics

Millard (1997) and Riedel (2000) place the family in the superfamily Cassoidea, Ponder & Lindberg (1997) and Bouchet & Rocroi (2006) in the superfamily Tonnoidea. The family name Cassoidea was established by Latreille as early as 1825 and thus clearly had priority over Tonnoidea Suter, 1913 (cf. IRZN ).

The Ranellidae family is divided into two subfamilies:

Cabestana cutacea (Linnaeus, 1767) from the coast of South Africa

literature

  • Philippe Bouchet, Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda. In: Malacologia. 47: 239-283, Ann Arbor 2005, ISSN  0076-2997 , archive.org , ConchBooks, ISBN 978-3-925919-72-5 .
  • Victor Millard (Ed.): Classification of the Mollusca. A Classification of World Wide Mollusca. Rhine Road, South Africa 1997, ISBN 0-620-21261-6 , online (PDF; 2.46 MB), at olivirv.myspecies.info, accessed February 25, 2017.
  • Betty Jean Piech: Ranellidae And Personidae: A Classification Of Recent Species. 60 pp., Delaware Museum of Natural History, Wilmington Del. 1995, OCLC 33600855 .
  • Winston Ponder & David Lindberg : Towards a phylogeny of gastropod molluscs; an analysis using morphological characters. In: Zoological Journal of the Linnean Society. 119: 83-265, London 1997, ISSN  0024-4082 , doi: 10.1111 / j.1096-3642.1997.tb00137.x .
  • Frank Riedel: Origin and evolution of the "higher" Caenogastropoda. Berliner Geoscientific Abhandlungen, Series E, Volume 32, Berlin 2000, ISBN 3-89582-077-6 .
  • Richard Semon : On the purpose of excreting free sulfuric acid in sea snails. Biologisches Centralblatt 9, 1890, p. 80, online at biodiversitylibrary.org, accessed on February 25, 2017.

Web links

Commons : Triton snails (Ranellidae)  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Hugh Govan: Cymatium muricinum and Other Ranellid Gastropods: Major Predators of Cultured Tridacnid Clams (PDF; 3.0 MB) . ICLARM Technical Reports 49. Manila, 1995. 150 pages.