Aplysiidae

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Aplysiidae
Aplysia californica.jpg
Aplysia californica , a typical sea hare, shown here releasing a cloud of purple pigment, probably as a reaction to being disturbed.
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Clade: Euopisthobranchia
Clade: Anaspidea
Superfamily: Aplysioidea
Family: Aplysiidae
Lamarck, 1809
Genera

See text.

Synonyms
  • Aplysiinae Lamarck, 1809 · accepted, alternate representation
  • Dolabriferidae (synonym)
  • Dolabriferinae Pilsbry, 1895 · accepted, alternate representation
  • Notarchinae Mazzarelli, 1893 · accepted, alternate representation

Aplysiidae is the only family in the superfamily Aplysioidea, within the clade Anaspidea. [1] These animals are commonly called sea hares because, unlike most sea slugs, they are often quite large, and when they are underwater, their rounded body shape and the long rhinophores on their heads mean that their overall shape resembles that of a sitting rabbit or hare. Sea hares are however sea snails with shells reduced to a small plate hidden between the parapodia, and some species are extremely large. The Californian black sea hare, Aplysia vaccaria is arguably the largest living gastropod species, and is certainly the largest living heterobranch gastropod.

Contents

Description

Dorsal view of a live Aplysia parvula showing general anatomy of sea hares. Aplysia parvula 2.png
Dorsal view of a live Aplysia parvula showing general anatomy of sea hares.

Members of the Aplysiidae have an atrophied inner shell (in contrast with the nudibranchs, which have no shell at all). In Aplysia and Syphonota, this shell is a soft flattened plate over the visceral rear end, where it is fully or partially enclosed in the mantle skin. In Dolabella auricularia, the shell is ear-shaped. The shell is only present in the larval stage of the two genera Bursatella and Stylocheilus, and on this basis they have been grouped into the subfamily Dolabriferinae. [2]

They are rather large animals. Their length can reach up to 75 cm (Aplysia vaccaria), and they can weigh well over 2 kg. They are cosmopolitan and found in temperate and tropical seas, inhabiting shallow coastal areas and sheltered bays, thick with vegetation.

The Aplysiidae are herbivorous, eating a variety of red, green or brown algae and eelgrass. Their color is diet-derived from the pigments of the algae. They concentrate the toxins found on algae.

Sea hare Dolabrifera dolabrifera Dolabrifera1.jpg
Sea hare Dolabrifera dolabrifera

Defenses

Some species spout ink when disturbed or attacked, and they may also swim (rather than crawl) away, using their broad wing-like flaps or parapodia. The ink is extracted from their algal food, rather than being synthesized. [3]

Sea hares have two main secretory glands in their mantle cavity.

The genus Aplysia has proved useful as a model in neurobiology for the study of electrical synapses, which mediate the release of the clouds of ink. [4]

Mating habits

Sea hares are hermaphrodites, with fully functional male and female reproductive organs. The penis is on the right side of the head while the vagina is situated in the mantle cavity, beneath the shell, deep down between the parapodia. It is therefore physically impossible for mating partners to act as both male and female at the same time. [5]

They have unusual mating habits: they can mate in pairs with one acting as a male, the other as a female, but they commonly occur in quite crowded numbers during the mating season, and this often leads to chains of three or more sea hares mating together. The one at the front acts as a female and the one at the back as a male. The animal(s) in between are acting as both males and females, in other words, the animal receiving sperm passes its own sperm to a third sea hare.

Predators

Predators include pycnogonid sea spiders, wrasses and sea turtles.

Laboratory use

Following the lead of Ladislav Tauc and his pupil Eric R. Kandel, [6] [7] Aplysia has been studied as a model organism by neurobiologists, because its gill and siphon withdrawal reflex, as studied in Aplysia californica, is mediated by electrical synapses, which allow several neurons to fire synchronously. 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. [8] Also, the 'tongue' on the underside is controlled by only two neurons, which allowed complete mapping of the innervation network to be carried out. [9]

Taxonomy

A 2004 study [10] has shown that Aplysiidae is a monophyletic taxon with two distinct clades: Aplysiinae and Dolabellinae + Dolabriferinae + Notarchinae.

The authority of this family is still somewhat in dispute. The family was incorrectly originally spelled as Laplysiana. This was a Latinized form of the original common name "les Laplysiens" as described in Philosophie zoologique, 1:320 by Lamarck in 1809. [11] Rafinesque introduced the new name Laplysinia in 1815. In 2001 Bouchet & Rocroi advocated the attribution of the name Aplysiidae to Lamarck. [12]

Subfamilies

Classification after N. B. Eales (1984): [13]

Genera

Genera brought into synonymy

Related Research Articles

<span class="mw-page-title-main">California sea hare</span> Species of gastropod

The California sea hare is a species of sea slug in the sea hare family, Aplysiidae. It is found in the Pacific Ocean, off the coast of California in the United States and northwestern Mexico.

<span class="mw-page-title-main">Anaspidea</span> Clade of gastropods

The clade Anaspidea, commonly known as sea hares, are medium-sized to very large opisthobranch gastropod molluscs with a soft internal shell made of protein. These are marine gastropod molluscs in the superfamilies Aplysioidea and Akeroidea.

<i>Bursatella leachii</i> Species of gastropod

Bursatella leachii, whose common name is the ragged sea hare or shaggy sea hare, is a species of large sea slug: a marine gastropod mollusk in the sea hare family Aplysiidae. It has an almost pantropical distribution, from the Mediterranean to the Caribbean, but excluding the central and eastern Pacific Ocean. Its long planktonic larval period and short life cycle make able to colonise new areas and increase dramatically in number if food supplies are favourable.

<i>Dolabella</i> (gastropod) Genus of gastropods

Dolabella is a genus of sea slugs or sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.

<i>Notarchus</i> Genus of molluscs

Notarchus is a genus of sea slugs or sea hares, marine opisthobranch gastropod mollusks in the family Aplysiidae, the sea hares.

<i>Petalifera</i> Genus of molluscs

Petalifera is a genus of sea slugs or sea hares, marine gastropod mollusks belonging to the family Aplysiidae, the sea hares.

<i>Aplysia</i> Genus of sea slugs

Aplysia is a genus of medium-sized to extremely large sea slugs, specifically sea hares, which are a kind of marine gastropod mollusk.

<i>Bulla</i> (gastropod) Genus of gastropods

Bulla is a genus of medium to large hermaphrodite sea snails, shelled marine opisthobranch gastropod molluscs. These herbivorous snails are in the suborder Cephalaspidea, headshield slugs, and the order Opisthobranchia.

<i>Scutus</i> Genus of gastropods

Scutus is a genus of large sea snails or limpets with the common name "shield shells". These are marine gastropod molluscs in the family Fissurellidae, the keyhole limpets and slit limpets.

<span class="mw-page-title-main">Fissurellidae</span> Family of limpet-like sea snails

Fissurellidae, common name the keyhole limpets and slit limpets, is a taxonomic family of limpet-like sea snails, marine gastropod molluscs in the clade Vetigastropoda. Their common name derives from the small hole in the apex of their cone-like shells. Although superficially resembling "true" limpets, they are in fact not closely related to them.

<i>Buccinum</i> Genus of gastropods

Buccinum is a genus of medium-sized sea snails, marine gastropod molluscs in the family Buccinidae, the true whelks.

<i>Carinaria</i> Genus of gastropods

Carinaria is a genus of medium-sized floating sea snails, pelagic gastropod molluscs in the family Carinariidae.

<i>Aplysia fasciata</i> Species of gastropod

Aplysia fasciata, common name the "mottled sea hare", or the "sooty sea hare", is an Atlantic species of sea hare or sea slug, a marine opisthobranch gastropod mollusk in the family Aplysiidae.

<i>Aplysia dactylomela</i> Species of gastropod

Aplysia dactylomela, the spotted sea hare, is a species of large sea slug, a marine opisthobranch gastropod in the family Aplysiidae, the sea hares.

<i>Aplysia vaccaria</i> Species of gastropod

Aplysia vaccaria, also known as the black sea hare and California black sea hare, is a species of extremely large sea slug, a marine, opisthobranch, gastropod mollusk in the family Aplysiidae. It is the largest sea slug species.

<i>Ovula</i> Genus of gastropods

Ovula is a genus of sea snails, marine gastropod mollusks in the family Ovulidae.

Aplysia morio, the Atlantic black sea hare or sooty sea hare, is a species of sea slug, a marine gastropod mollusk in the family Aplysiidae, the sea hares. It lives in warm waters in the Caribbean Sea and off the south and southeastern coast of the United States, where it feeds on seaweed.

<i>Stylocheilus striatus</i> Species of gastropod

Stylocheilus striatus is a species of sea hare found in the Indo-pacific region living from the intertidal zone to a depth of 30 metres. Common names include lined sea hare, blue ring sea hare and furry sea hare. Mature animals can reach sizes of up to 65 mm in length and are brown in colour with blue spots. Their diet mainly consists of blue algae. They play an important role in controlling toxic blooms of the cyanobacterium Lyngbya majuscula.

References

  1. ↑ MolluscaBase eds. (2021). MolluscaBase. Aplysiidae Lamarck, 1809. Accessed on 2021-01-27.
  2. ↑ Paige, John A. (January 1988). "Biology, Metamorphosis and Postlarval Development of Bursatella leachii plei Rang (Gastropoda: Opisthobranchia)". Bulletin of Marine Science. 42 (1): 65–75.
  3. ↑ Zsilavecz, G. 2007. Nudibranchs of the Cape Peninsula and False Bay. ISBN   0-620-38054-3
  4. ↑ Kandel E. R., Schwartz J. H. & Jessell T. M. (2000). Principles of Neural Science , 4th ed., New York, McGraw-Hill 180 pp.
  5. ↑ Vue Z., Kamel B. S., Capo T. R., Bardales A. T. & Medina M. (2014). "Comparative analysis of early ontogeny in Bursatella leachii and Aplysia californica". PeerJ 2: e700 doi : 10.7717/peerj.700
  6. ↑ Kandel, E.R. (1979) Behavioural Biology of Aplysia. San Francisco, W.H.Freeman & Co. 463pp.
  7. ↑ Foundation, Lasker. "Eric Kandel: Learning about the human brain from sea slugs". The Lasker Foundation. Retrieved 2020-11-12.
  8. ↑ Redish, Edward F. (2003). ""Chapter 2: Cognitive Principles and Guidelines for Instruction".". Teaching physics : with the physics suite. Hoboken, NJ: John Wiley & Sons. ISBN   0-471-39378-9. OCLC   53287676.
  9. ↑ Agranoff, Bernard W.; Cotman, Carl W.; Uhler, Michael D. (1999). "Invertebrate Learning and Memory". Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition.
  10. ↑ Klussmann‐Kolb, A. (2004). "Phylogeny of the Aplysiidae (Gastropoda, Opisthobranchia) with new aspects of the evolution of seahares". Zoologica Scripta. 33 (5): 439–462. doi:10.1111/j.0300-3256.2004.00158.x.
  11. ↑ Lamarck, J.B. (1809). Philosophize zoologique. Paris: Dentu. p. 428.
  12. ↑ Bouchet, P. & J.P. Rocroi (2001). "Corrections of Authorship and date for gastropod (Mollusca) family-group names placed on the Official List and Official Index". Bulletin of Zoological Nomenclature. 58 (3): 170–178.
  13. ↑ "Notes on cephalaspideans". Opisthobranch. 16 (3): 26. 1984.
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