Aplysia

Aplysia
California sea hare ( Aplysia californica ) with cloud of ink
Systematics
Superordinate : Heterobranchia Order : Hind gill snails (Opisthobranchia) Subordination : Broad- footed snails (Anaspidea) Superfamily : Aplysioidea Family : Aplysiidae Genre : Aplysia
Scientific name
Aplysia
CN Linnaeus , 1767

Aplysia (German sea ​​hare , not to be confused with the fish family of the same name, Cyclopteridae or the edible sea ​​hare ) are a genus of sea ​​snails of the order hind gill snails ( Opisthobranchia ). They are best known because they produce some of the largest known snails : specimens of Aplysia vaccaria reach a length of up to 75 cm and weigh around 2 kg (4.4 lb). Nevertheless, there are species that are only about 2–6 cm tall. The evolutionary regression of the shell is at the middle level within the broad-footed snails. that is, they still have a shell, which is no longer external, but internal. It is located in the abdomen above the viscera and is completely embedded in tissue.

The particularly large neurons and the not overly complicated, manageable nervous system make them, especially Aplysia californica , an excellent research subject in neurology . Said Huber explored Eric R. Kandel at their synapses u. a. learning at the cellular level.

The German name Seehase (English sea ​​hare , French lièvre de mer ) probably comes from its head shape, because in the water the front part with the flat pharyngeal tentacles and the rhinpheres with the underlying eyes resemble a hare's head with a little imagination, especially when that Animal with the massive rear part stretches its head forward and up.

Way of life

The mantle flaps have different functions. On the one hand, this increases the standing width. Other species use them to swim with them with regular, wave-like contractions. The parapodial lobes then have a wing shape that extends sideways from the body.

Sea hares live after the larval stage, which is often spent as floating plankton, mostly on the sea floor. They colonize areas with denser vegetation, which provides them with food and shelter. This makes them part of the benthos . However, some species such as Aplysia brasiliana can swim freely and cover even greater distances.

Sea hares are vegetarian. They eat different algae, Tang and seagrass species . The rasp tongue ( radula ) is used to rasp off parts of the plant, which then run through the digestive tract. With the plant parts also food growth such. B. ingested smaller algae species.

A characteristic of many species is the ability to create an intense purple cloud of ink for defense. According to the current state of knowledge, this dye is obtained from eaten red algae and is released into the environment through special glands on the back.

To protect against predators, there are species that also store the toxin aplysia toxin . This toxin is a product of the blue algae species (cyanobacteria), which grow on certain types of seaweed and are ingested by the snails when they eat. As far as the eaten blue-green algae are concerned, the species Lyngbya majuscula is mainly cited as a food source for snails. In addition to Lyngbya majuscula, however, other types of blue-green algae of the genera Schizothrix and Planktothrix are known from which snails can extract aplysia toxin and which are therefore a possible source of poison.

Internal system

Many species of the genus Aplysia have been found and described over time. However, not every species seems to be new; many synonyms are assumed. The reason for this is that some species exist far more globally than assumed, that the discoveries and sightings are local and that a network only took place in the last few years, and that so far there has only been one revision of Aplysia by N. B. Eales (1960). This resulted in 36 species. Since then there have been other species descriptions.

A selection of Apylsia species are:

• Aplysia brasiliana (Spotted Sea Hare) - S. Rang, 1828 (possibly = Aplysia fasciata )
  • Distribution: West Atlantic from New Jersey to Brazil; East Atlantic (around Ghana)
  • Length: up to 27 cm
  • Color: variable
• Aplysia californica (California sea hare) - JG Cooper, 1863
• Aplysia cedrocensis  - P. Bartsch & HA Rehder, 1939
• Aplysia cervina  - Dall, WH and Simpson, CT 1901
• Aplysia dactylomela (Curled Sea Hare) - S. Rang, 1828
  • Distribution: worldwide in tropical and temperate seas
  • Color: from light gray to green to dark brown
  • large black rings on the surface; not buoyant
• Aplysia depilans (Marbled Sea Hare) - Gmelin , 1791
  • Distribution: Eastern Atlantic, Mediterranean
  • thin, yellow inner shell; relatively likes to swim
• Aplysia donca  - Ev. Marcus and Er. Marcus, 1960
  • Distribution: North America, West Atlantic
• Aplysia extraordinaria  - JK Allan, 1932 (possibly = Aplysia gigantea )
  • Distribution: Western Australia, New Zealand
  • Length: about 40cm
• Aplysia fasciata  - Poiret, 1798 (possibly = Aplysia brasiliana ).
  • Distribution: East Atlantic, West Africa
  • Length: 40 cm
  • Color: dark brown to black
  • sometimes a red stripe delimits the parapodia and mouth tentacles
• Aplysia geographica  - A. Adams & LA Reeve, 1850
• Aplysia gigantea  - GB Sowerby, 1869
  • Distribution: Western Australia
  • Length: 60 cm
  • Color: dark brown to black
  • Skin secretions are very disgusting; washed ashore specimens are said to be responsible for the death of dogs
• Aplysia juliana  - JRC Quoy & JP Gaimard , 1832
  • Distribution: Worldwide, in all warm seas.
  • Color: various, from gray to light brown.
  • no purple gland, therefore no ink release; the back of the foot can be used as a suction cup
• Aplysia kurodai  - K. Baba, 1937
  • Distribution: NW Pacific
  • Length: 30 cm
  • Color: dark brown to purple-black, dotted with white spots.
• Aplysia morio (Atlantic black sea hare) - AE Verrill , 1901
  • Distribution: Eastern Atlantic
  • Length: 40 cm
  • Color: black to deep brown, no spots
• Aplysia oculifera  - A. Adams & LA Reeve, 1850
  • Distribution: Indian Ocean, Western Pacific
  • small brown eye spots
• Aplysia parvula (Little Sea Hare) - OAL Guilding in Mørch, 1863
  • Distribution: worldwide in warm to temperate seas
  • Length: 6 cm
  • Color: brown to green spots
• Aplysia punctata (common sea hare) - G. Cuvier , 1803
  • Distribution: Mediterranean and parts of the north-east Atlantic
  • Length: mostly 15, max. 20 cm
  • Color: with light spots and dots, basic color very variable
  • rarely swims
• Aplysia reticulopoda  - RD Beeman, 1960
• Aplysia sagamiana  - K. Baba, 1955
  • Distribution: Eastern Australia, Japan
• Aplysia sibogae  - Bergh, 1905 (possibly = Aplysia juliana )
• Aplysia sydneyensis  - GB Sowerby, 1869
  • Distribution: Australia
  • Length: 15 cm
  • not clearly described
• Aplysia vaccaria ( California black sea hare ) - LR Winkler, 1955 (possibly = Aplysia cedrocensis )
  • Distribution: California Pacific coast
  • Length: very large (up to 75 cm)
  • Color: Black
  • no purple ink; large inner shell
• Aplysia willcoxi  - A. Heilprin, 1886

External system

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). A current phylogenetically oriented system goes back to Bouchet & Rocroi (2005).

Taxonomy by Bouchet & Rocroi (2005)

According to the taxonomy of Bouchet & Rocroi (2005) , the Aplysia are a genus within the clade of the diverse gills ( heterobranchia ):

• Class Gastropoda Cuvier , 1797
  • Clade Heterobranchia Gray , 1840
    • informal group Opisthobranchia Milne Edwards , 1848
      • Klade Aplysiomorpha P. Fischer , 1883
        • Superfamily Aplysioidea Lamarck , 1809
          • Family Aplysiidae Rafinesque , 1815
            • Genus Aplysia Linnaeus , 1767

Taxonomy by Ponder & Lindberg (1997)

According to the taxonomy of Ponder & Lindberg (1997) , the Aplysidea are an order within the superordinate order of the Diverse-Kiemer ( Heterobranchia ):

• Class Gastropoda Cuvier, 1797
  • Subclass Orthogastropoda W.F. Ponder & DR Lindberg , 1996
    • Subclass Apogastropoda Salvini-Plawen & Haszprunar , 1987
      • Parent Heterobranchia Gray, 1840
        • Order Opisthobranchia Milne Edwards, 1848
          • Suborder Anaspidea P. Fischer, 1883
            • Superfamily Aplysioidea Lamarck, 1809
              • Family Aplysiidae Rafinesque, 1815
                • Genus Aplysia Linnaeus, 1767

Web links

Commons : Aplysia  - collection of images, videos and audio files

• http://www.nudipixel.net - Nudi Pixel: Aplysiidae, pictures

Not Found The requested URL / subclass / aplysiidae was not found on this server.

• http://www.seaslugsofhawaii.com - Aplysia: pictures, dates
• What is Aplysia californica?
• http://www.kinder-tierlexikon.de/s/seehase.htm - Children's animal lexicon

Individual evidence

1. ^ GW Gribble: The diversity of naturally occurring organobromine compounds. In: Chem. Soc. Rev. 28 ; 1999, 335-346; doi : 10.1039 / a900201d .
2. ↑ GH Habermehl: Poison - animals and their weapons. 5. update u. exp. Edition, Springer Verlag, Berlin 1994, ISBN 3-540-56897-2 , p. 24 f.
3. ^ NB Eales: Revision of the world species of Aplysia (Gastropoda, Opisthobranchia). Bulletin of the British Museum (Natural History), In: Zoology. 5 (10): 1960, 267-404, OCLC 17684318 .
4. ^ WB Rudman: December 22, 2006; Comment on Aplysia willcoxi - a junior synonym of A. brasiliana? In: Sea Slug Forum; Australian Museum, Sydney; http://www.seaslugforum.net/find/19011
5. ^ JG Cooper: On new or rare mollusca inhabiting the coast of California. No. II, Proceedings of the Californian academy of Science 3 (1): 56-60; 1863, archive.org .
6. ^ WH Dall & CT Simpson: The Mollusca of Porto Rico. US Fisheries Commission Bulletin, 20: 1901, 351-524, pls. 53-58, online at babel.hathitrust.org, accessed February 26, 2017.
7. ↑ S. Rank: Histoire naturelle des Aplysiens, prèmiere famille de l'ordre des Tectibranches. 84 pages, Plates 1-24; In: D. Férussac: Histoire naturelle generale et particuliere des Mollusques. Firmin Didot: Paris 1828, online at biodiversitylibrary.org, accessed February 26, 2017.
8. ^ JK Allan: A new genus and species of sea-slug, and two new species of sea-hares from Australia. Records of the Australian Museum 18 (6): 1932, 314-320, doi : 10.3853 / j.0067-1975.18.1932.736 .
9. ^ GB Sowerby: Monograph of the Genus Aplysia Plates 1-10. In: Conchologia Iconica. Vol. 17, LA Reeve, London 1870 online at biodiversitylibrary.org, accessed February 26, 2017.
10. ↑ JR Quoy & JP Gaimard: Zoology. 1830-1833; In: Voyage de decouvertes de L'Astrolabe pendant les annees 1826-1827-1828-1829, sous le commandement de MJ Dumont D'Urville capitaine de vaisseau. Paris, Tastu, 1830-1835.
11. ^ K. Baba: Opisthobranchia of Japan (I). In: Journal of the Department of Agriculture. Kyushu Imperial University, 5 (4): 1937, 195-236. (Pl.4)
12. ↑ MOAL Mörch: Contributions a la faune malacologique des Antilles danoises. In: Journal de Conchyliologie. 11: 1863, 21-43, archive.org .
13. ^ K. Baba: Opisthobranchia of Sagami Bay. Supplement, Iwanami Shoten: Tokyo 1955. 59 pp., 20 plates.
14. ^ GB Sowerby: Aplysia. In: Conchologia Iconica. Vol. 17, LA Reeve, London 1870.
15. ^ LR Winkler: A new species of Aplysia on the southern California coast. Bull. South. Calif. Acad. Sci. 54 (1): 1955, 5-7, archive.org .
16. ^ A. Heilprin : A new species of Aplysia. In: Proc acad nat sci Philadelphia. 3: 1886,364.
17. ↑ Thiele, J. (1929–1935): Handbook of systematic molluscology. 2 volumes. 1-1154.
18. ^ R. Bieler & PM Mikkelsen (Sci.Ed.); JS Bhatti (Transl.); J. Thiele : Handbook of systematic 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. OCLC 680545970 .
19. ^ Ponder, WF and Lindberg, DR : Towards a phylogeny of gastropod molluscs: an analysis using morphological characters. In: Zoological Journal of the Linnean Society. Volume 119, No. 2, 1997, pp. 83-265; doi : 10.1111 / j.1096-3642.1997.tb00137.x
20. ↑ Bouchet, P. & Rocroi, J.-P .: Part 2. Working classification of the Gastropoda. In: Malacologia. Volume 47, pp. 239-283, Ann Arbor 2005; ISSN  0076-2997 , archive.org , ConchBooks, ISBN 978-3-92591972-5 .
21. ↑ Bouchet, P. & Rocroi, J.-P. (Eds.): J. Frýda, B. Hausdorf., WF Ponder, Á. Valdés & A. Warén: Classification and nomenclator of gastropod families. In: Malacologia: International Journal of Malacology Volume 47, Nos. 1-2; ConchBooks, Hackenheim 2005; ISBN 3-925919-72-4 , ISSN  0076-2997 ; http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278
22. ↑ GT Poppe & SP Tagoro: February 23, 2006; The New Classification of Gastropods according 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.