Aplysia

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Aplysia
Aplysia californica.jpg
Aplysia californica releasing a cloud of ink
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Heterobranchia
clade Euthyneura
clade Euopisthobranchia
clade Aplysiomorpha
Superfamily: Aplysioidea
Family: Aplysiidae
Genus: Aplysia
Linnaeus, 1767
Type species
Aplysia depilans Gmelin, 1791
Species

See text

Synonyms

Laplysia Linnaeus, 1767 (incorrect spelling)

Aplysia is a genus of medium-sized to extremely large sea slugs, specifically sea hares, which are one clade of large sea slugs, marine gastropod mollusks. The general description of sea hares can be found in the article on the superfamily Aplysioidea.

These benthic herbivorous sea hares can become rather large compared with most other mollusks. They graze in tidal and subtidal zones of tropical waters, mostly in the Indo-Pacific Ocean (23 species); but they can also be found in the Atlantic Ocean (12 species), with a few species occurring in the Mediterranean.

Aplysia species, when threatened, mostly release clouds of ink to blind the attacker. Following the lead of Eric R. Kandel, the genus has been studied as a model organism by neurobiologists, because its siphon-withdrawal response, as studied in Aplysia californica, is mediated by electrical synapses, which allow several neurons to fire synchronously (Kandel et al., 2000). (See : Aplysia gill and siphon withdrawal reflex) This quick neural response is necessary for a speedy reaction to danger by the animal. Aplysia has only about 20,000 neurons, making it a favorite subject for investigation by neuroscientists.[1] Also, the 'tongue' on the underside is controlled by only two neurons, which allowed complete mapping of the innervation network to be carried out.

Long term memory[edit]

In neurons that mediate several forms of long-term memory in Aplysia, the DNA repair enzyme poly ADP ribose polymerase 1 (PARP-1) is activated. In virtually all eukaryotic cells tested, the addition of polyADP-ribosyl groups to proteins (polyADP-ribosylation) occurs as a response to DNA damage. Thus the finding of activation of PARP-1 during learning and its requirement for long-term memory was surprising.[2] Cohen-Aromon et al.[2] suggested that fast and transient decondensation of chromatin structure by polyADP-ribosylation enables the transcription needed to form long-term memory without strand-breaks in DNA. Subsequent to these findings in Aplysia, further research was done with mice and it was found that polyADP-ribosylation is also required for long-term memory formation in mammals.[3]

Reproduction[edit]

The California sea hare, Aplysia californica, is a simultaneous hermaphrodite. A simultaneous (or synchronous) hermaphrodite is an adult organism that has both male and female sexual organs at the same time. A. californica has the ability to store and digest allosperm (sperm from a partner) and often mates with multiple partners. Studies of multiple matings in A. californica have provided insights on how conflicts between the sexes are resolved.[4] A potent sex pheromone, the water-borne protein attractin, is employed in promoting and maintaining mating in Aplysia. Attractin interacts with three other Aplysia protein pheromones (enticin, temptin or seductin) in a binary fashion to stimulate mate attraction.[5]

Species[edit]

Species within the genus Aplysia are as follows. This list follows the studies of Medina et al. who established a phylogenetic hypothesis for the genus Aplysia through study of the partial mitochondrial DNA (mtDNA) sequence data of ribosomal genes (rDNA).

An Aplysia fasciata (above) and a couple of Aplysia punctata (below) grazing in a tide pool in Póvoa de Varzim, Portugal.
  • Aplysia argus Rüppell & Leuckart, 1830
  • Aplysia californica (J.G. Cooper, 1863) California sea hare
    • Distribution : Northeast Pacific
  • Aplysia cedrocensis (Bartsch & Rehder, 1939)
    • Distribution : Northeast Pacific
  • Aplysia cervina (Dall & Simpson, 1901)
    • Distribution : West Atlantic
  • Aplysia cornigera Sowerby, 1869
    • Distributuion: Indian Ocean, West Pacific
  • Aplysia cronullae Eales, 1960
    • Distribution : Southwest Pacific
  • Aplysia dactylomela (Rang, 1828) Spotted sea hare
    • Distribution : Cosmopolitan; tropical and temperate seas.
    • Color : from pale gray to green to dark brown.
    • Description : large black rings on the mantle; good swimmer
  • Aplysia denisoni Smith, 1884
    • Distribution : Indian Ocean, West Pacific
  • Aplysia depilans (Gmelin, 1791)
    • Distribution : Northeast Atlantic, Mediterranean.
    • Description : thin, yellow inner shell
  • Aplysia dura Eales, 1960
    • Distribution : Southeast Atlantic, Southwest Pacific
  • Aplysia euchlora Adams in M.E.Gray, 1850
    • Distribution : Northwest Pacific
  • Aplysia extraordinaria (Allan, 1932) (possibly = Aplysia gigantea)
    • Distribution : Western Australia, New Zealand.
    • Length : more than 40 cm
  • Aplysia fasciata (Poiret, 1798) ( Aplysia brasiliana Rang, 1828 is a junior synonym).
    • Distribution : East Atlantic, Mediterranean, West Africa, Red Sea
    • Length : 40 cm
    • Color : dark brown to black.
    • Description : sometimes has a red border to the parapodia and oral tentacles;
  • Aplysia gigantea Sowerby, 1869
    • Distribution : Indian Ocean, West Pacific
  • Aplysia gracilis Eales, 1960 [citation needed]
    • Distribution : Red Sea
  • Aplysia inca d'Orbigny, 1837
    • Distribution : Southeast Pacific
  • Aplysia juliana (Quoy & Gaimard, 1832) Walking sea hare
    • Distribution: cosmopolitan, circumtropical in all warm seas
    • Color: various, from uniform to pale brown
    • Description: no purple gland, therefore no ink secretions; posterior end of the foot can act as a sucker
  • Aplysia keraudreni Rang, 1828
    • Distribution: South Pacific
    • Length: 25 cm
    • Color: dark brown
  • Aplysia kurodai (Baba, 1937)
    • Distribution: NW Pacific
    • Length: 30 cm
    • Color: dark brown to purplish black, dotted with white spots
  • Aplysia maculata Rang, 1828
    • Distribution : Western Indian Ocean
  • Aplysia morio (A. E. Verrill, 1901) Atlantic black sea hare, sooty sea hare
    • Distribution: Northwest Atlantic
    • Length: 40 cm
    • Color: black to deep brown; no spots
  • Aplysia nigra d'Orbigny, 1837
    • Distribution : Southwest Atlantic, South Pacific
  • Aplysia nigra brunnea Hutton, 1875
    • Distribution: New Zealand
    • Length: 10 cm
    • Color: dark brown
  • Aplysia oculifera (Adams & Reeve, 1850) Spotted sea hare
    • Distribution: Indian Ocean; West Pacific; common along the north, east and south coast of South Africa
    • Length: 15 cm
    • Description: greenish brown, with small brown to black spots with white centres
    • Habitat: shallow bays and estuaries
    • Behaviour: hides by day; emerges at night to feed on seaweed
  • Aplysia parvula (Guilding in Moerch, 1863) Pygmy sea hare, Dwarf sea hare
    • Distribution : worldwide in warm to temperate seas
    • Length: 6 cm
    • Color: brown to green spots
  • Aplysia punctata (Cuvier, 1803)
    • Distribution: NE Atlantic
    • Length: 20 cm
    • Color: very variable
  • Aplysia rehderi Eales, 1960
    • Distribution : Northeast Pacific
  • Aplysia reticulata Eales, 1960
    • Distribution : Southwest Pacific
  • Aplysia reticulopoda (Beeman, 1960) Net-foot sea hare
    • Distribution : Northeast Pacific
  • Aplysia robertsi Pilsbry, 1895
    • Distribution : Northeast Pacific
  • Aplysia rudmani Bebbington, 1974
    • Distribution : Indian Ocean
  • Aplysia sagamiana (Baba, 1949)
    • Distribution: East Australia, Japan; Northwest Pacific
  • Aplysia sibogae (Bergh, 1905) (?)(probably = Aplysia juliana)
  • Aplysia sowerbyi Pilsbry, 1895
    • Distribution : Southwest Pacific
  • Aplysia sydneyensis (Sowerby, 1869)
    • Distribution: Australia
    • Length: 15 cm
    • Description: not clearly defined
  • Aplysia tanzanensis Bebbington, 1974
    • Distribution : Indian Ocean
  • Aplysia vaccaria (Winkler, 1955) California black sea hare (possibly  ?= Aplysia cedrocensis)
    • Distribution: Pacific Coast of California
    • Length: very big – up to 75 cm
    • Color: black
    • Description: no purple ink; huge internal shell
Species brought into synonymy
  • Aplysia aequorea Heilprin, 1888 : synonym of Aplysia dactylomela Rang, 1828
  • Aplysia albopunctata Deshayes, 1853 : synonym of Aplysia punctata (Cuvier, 1803)
  • Aplysia angasi G.B. Sowerby II, 1869: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia annulifera Thiele, 1930: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia ascifera Rang, 1828: synonym of Dolabrifera dolabrifera (Rang, 1828)
  • Aplysia benedicti Eliot, 1899: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia bourailli Risbec, 1951: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia brasiliana (Rang, 1828) Mottled sea hare, sooty sea hare (junior synonym of Aplysia fasciata; different geographical populations of the same species) : synonym of Aplysia fasciata Poiret, 1789
  • Aplysia cirrhifera Quoy & Gaimard, 1832: synonym of Barnardaclesia cirrhifera (Quoy & Gaimard, 1832)
  • Aplysia concava Sowerby, 1869: synonym of Aplysia parvula Mørch, 1863
  • Aplysia depressa Cantraine, 1835: synonym of Phyllaplysia depressa (Cantraine, 1835)
  • Aplysia dolabrifera Rang, 1828: synonym of Dolabrifera dolabrifera (Rang, 1828)
  • Aplysia donca (Ev. Marcus & Er. Marcus, 1960): synonym of Aplysia morio (A. E. Verrill, 1901)
  • Aplysia fimbriata Adams & Reeve, 1850: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia geographica (Adams & Reeve, 1850): synonym of Syphonota geographica (A. Adams & Reeve, 1850)
  • Aplysia hybrida Sowerby, 1806: synonym of Aplysia punctata (Cuvier, 1803)
  • Aplysia longicauda Quoy & Gaimard, 1825: synonym of Stylocheilus longicauda (Quoy & Gaimard, 1825)
  • Aplysia megaptera Verrill, 1900 : synonym of Aplysia dactylomela Rang, 1828
  • Aplysia nettiae Winkler, 1959: synonym of Aplysia californica J. G. Cooper, 1863
  • Aplysia norfolkensis Sowerby, 1869: synonym of Aplysia parvula Mørch, 1863
  • Aplysia oahouensis Souleyet, 1852: synonym of Dolabrifera dolabrifera (Rang, 1828)
  • Aplysia ocellata d'Orbigny, 1839: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia odorata Risbec, 1928: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia operta Burne, 1906: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia petalifera Rang, 1828: synonym of Petalifera petalifera (Rang, 1828)
  • Aplysia protea Rang, 1828: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia pulmonica Gould, 1852 : synonym of Aplysia argus Rüppell & Leuckart, 1830
  • Aplysia radiata Ehrenberg, 1831: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia rosea Rathke, 1799: synonym of Aplysia punctata (Cuvier, 1803)
  • Aplysia schrammi Deshayes, 1857: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia scutellata Ehrenberg, 1831: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia sibogae Bergh, 1905: synonym of Aplysia juliana Quoy & Gaimard, 1832
  • Aplysia striata Quoy & Gaimard, 1832: synonym of Stylocheilus longicauda (Quoy & Gaimard, 1825)
  • Aplysia tigrina Rang, 1828: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia tigrinella Gray, 1850: synonym of Aplysia maculata Rang, 1828
  • Aplysia velifer Bergh, 1905</small: synonym of Aplysia dactylomela Rang, 1828
  • Aplysia willcoxi (Hellprin, 1886): synonym of Aplysia fasciata Poiret, 1789
  • Aplysia winneba Eales, 1957 : synonym of Aplysia fasciata Poiret, 1789

References[edit]

  1. ^ Redish, Edward F. (2003). "Chapter 2: Cognitive Principles and Guidelines for Instruction". Teaching Physics With The Physics Suite. Hoboken, New Jersey: John Wiley & Sons, Inc. p. 18. ISBN 978-0-471-39378-8. 
  2. ^ a b Cohen-Armon M, Visochek L, Katzoff A, Levitan D, Susswein AJ, Klein R et al. (2004). "Long-term memory requires polyADP-ribosylation". Science 304 (5678): 1820–2. doi:10.1126/science.1096775. PMID 15205535. 
  3. ^ Goldberg S, Visochek L, Giladi E, Gozes I, Cohen-Armon M (2009). "PolyADP-ribosylation is required for long-term memory formation in mammals". J. Neurochem. 111 (1): 72–9. doi:10.1111/j.1471-4159.2009.06296.x. PMID 19645746. 
  4. ^ Ludwig AN, Walsh PJ (2008). "Multiple mating, sperm storage, and mating preference in Aplysia californica". Biol. Bull. 215 (3): 265–71. PMID 19098147. 
  5. ^ Cummins SF, Nichols AE, Schein CH, Nagle GT (2006). "Newly identified water-borne protein pheromones interact with attractin to stimulate mate attraction in Aplysia". Peptides 27 (3): 597–606. doi:10.1016/j.peptides.2005.08.026. PMID 16309784. 
  • Howson, C.M.; Picton, B.E. (Ed.) (1997). The species directory of the marine fauna and flora of the British Isles and surrounding seas. Ulster Museum Publication, 276. The Ulster Museum: Belfast, UK. ISBN 0-948150-06-8. vi, 508 (+ cd-rom) pp
  • Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 180-213

External links[edit]

  • SEM images of its radula can be found at Thompson; Bebbington (1973). "Scanning electron microscope studies of gastropod radulae". Malacologia 14: 147–165. 
  • Photos of Aplysia - MondoMarino.net