Oar snails

Oar snails
Clione limacina , the largest species of oar snail
Systematics
Trunk : Molluscs (mollusca) Class : Snails (gastropoda) Subclass : Orthogastropoda Superordinate : Heterobranchia Order : Hind gill snails (Opisthobranchia) Subordination : Oar snails
Scientific name
Gymnosomata
HDM de Blainville , 1848

The oar snails ( gymnosomata formed from ancient Greek γυμνός gymnós , German 'naked' and τό σωμάτιον tó somátion , German 'small body' ; literally 'naked body') are a subordination of the pelagic hindgill snails . The oar snails are all very small: the largest species, Clione limacina , measures up to 5 cm.

features

In adaptation to their pelagic way of life, the bilaterally symmetrical , mostly colorless, transparent oar snails have no shell . Their foot has the shape of two wing-shaped lobes (parapodia) with which they actively move by rowing. Despite their outward similarity, they are not closely related to the Thecosomata . When it comes to rowing speed, they clearly surpass them.

The oar snails prey on zooplankton with the help of tentacle-like appendages on the mouth, often also snails of the suborder Thecosomata.

Systematics

The taxonomy of snails is subject to revision and change. Therefore there are different classifications. The one that goes back to J. Thiele (1929–1935) is usually considered classic . It was recognized until the 1990s. A more modern and the last one established on the basis of purely morphological approaches is that of Ponder & Lindberg (1997). The current system is phylogenetically oriented and goes back to Bouchet & Rocroi (2005).

The Gymnosomata used to belong to the group of pteropods ( Pteropoda ) that existed well into the 20th century . At the end of the 19th century the Pteropoda formed an order of the Gastropoda, and at the beginning of the 20th century even a separate class of molluscs. In more modern taxonomies, the gymnosomata form a subordination or have a comparable rank.

Systematics according to Bouchet & Rocroi (2005)

• Class Gastropoda G. Cuvier, 1797
  • Klade Heterobranchia JE Gray, 1840
    • informal group Opisthobranchia H. Milne Edwards, 1848
      • Klade Gymnosomata HDM de Blainville, 1848
        • Superfamily Clionoidea CS Rafinesque, 1815
          • Family Clionidae CS Rafinesque, 1815
          • Family Cliopsidae Costa, 1873
          • Family Notobranchaeidae Pelseneer, 1886
          • Family Pneumodermatidae PA Latreille, 1825
        • Superfamily Hydromyloidea A. Pruvot-Fol, 1942 (1862)
          • Family Hydromylidae A. Pruvot-Fol, 1942
          • Family Laginiopsidae A. Pruvot-Fol, 1922

Compared to Ponder & Lindberg (1997), families are more strongly divided into two superfamilies. The previous family Thliptodontidae (Kwietniewski, 1910) is losing its independence in this system as the subfamily Thliptodontinae of the family Clionidae.

Systematics according to Ponder & Lindberg (1997)

• Class Gastropoda G. Cuvier, 1797
  • Subclass Orthogastropoda WF Ponder & DR Lindberg, 1996
    • Subclass Apogastropoda L. Salvini-Plawen & G. Haszprunar, 1987
      • Superorder Heterobranchia JE Gray, 1840
        • Group Euthyneura JW Spengel, 1881
          • Order Opisthobranchia H. Milne Edwards, 1848
            • Suborder Gymnosomata HDM de Blainville, 1848
              • Family Clionidae CS Rafinesque, 1815
              • Family Cliopsidae Costa, 1873
              • Family Hydromylidae A. Pruvot-Fol, 1942
              • Family Laginiopsidae A. Pruvot-Fol, 1922
              • Family Notobranchaeidae Pelseneer, 1886
              • Family Pneumodermatidae PA Latreille, 1825
              • Family Thliptodontidae Kwietniewski, 1910

Web links

Commons : Rudders  - Collection of images, videos and audio files

• http://sn2000.taxonomy.nl Taxonomy
• www.marinespecies.org - taxonomy, literature references
• www.seaslugforum.net - Sea Slug Forum: Technical discussions, pictures

literature

• Mollusca - The Southern Synthesis Order Gymnosomata by L. Newman pages 985-989; Beesley, PL, Ross, GJB & Wells, A (eds) - ISBN 0-643-05756-0

Individual evidence

1. ↑ Thiele, J. (1929-1935). "Handbook of Systematic Molluscology". 2 volumes. 1-1154.
2. ↑ Bieler, R. & Mikkelsen, PM (Sci.Ed.); Bhatti, JS (Transl.); Thiele, J. "Handbuch der systematis molluscology", English: "Handbook of systematic malacology". Publ: Washington, DC; Smithsonian Institution Libraries; National Science Foundation; 1992-. Content: pt. 1. Loricata; Gastropoda: Prosobranchia - pt. 2. Gastropoda: Opisthobranchia and Pulmonata - pt. 3. Scaphopoda / Bivalvia / Cehalopoda - pt. 4. Comparative Morphology / Phylogeny / Geographical Distribution. Catalog-No: (OCoLC) ocm16004796
3. ^ Ponder, WF & Lindberg, DR (1997). "Towards a phylogeny of gastropod molluscs: an analysis using morphological characters" . Zoological Journal of the Linnean Society 119 (2): 83-265. doi : 10.1111 / j.1096-3642.1997.tb00137.x
4. ↑ Bouchet, P. & Rocroi, J.-P .: Part 2. "Working classification of the Gastropoda". Malacologia, 47: 239-283; Ann Arbor 2005; ISSN  0076-2997
5. ↑ Bouchet, P. & Rocroi, J.-P. (Ed.): Frýda, J., Hausdorf, B., Ponder, WF, Valdés, Á. & Warén, A. (2005). "Classification and nomenclator of gastropod families". Malacologia: International Journal of Malacology 47 (1-2). ConchBooks: Hackenheim, Germany. ISBN 3-925919-72-4 . ISSN 0076-2997 . 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278  
6. ↑ Poppe, GT & Tagoro, SP 23 February 2006. "The New Classification of Gastropods gemäß to Bouchet & Rocroi, 2005". PDF ( Memento of the original from September 27, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.