Aplysia gigantea

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Aplysia gigantea
Aplysia gigantea.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Clade: Euopisthobranchia
Clade: Anaspidea
Superfamily: Aplysioidea
Family: Aplysiidae
Genus: Aplysia
Species:
A. gigantea
Binomial name
Aplysia gigantea
Wells, 1986

Aplysia gigantea is a species of sea slug, a shell-less marine gastropod mollusk in the family Aplysiidae. The species was first described in the Journal of the Malacological Society of Australia in 1869. [1] A. gigantea is also known more commonly as the sea hare due to their posterior chemosensory tentacles resembling a hare's ear. [2] A. gigantea is the largest known species in Australia of the opisthobranch genus. [3] The species is known to have toxic effects on terrestrial organisms, particularly domestic dogs. [4] Exposure to this species with dogs has been associated with the development of neurotoxicosis, with symptoms ranging from respiratory distress to tremors, muscle fasciculations, and seizures. [4]

Contents

Distribution

Aplysia gigantea are commonly found near the southwestern corner of Western Australia, in soft sediment or reef environments. [2] They are found in shallow water, ranging from 0-20m in depth. [2] A. gigantea are most commonly witnessed from January to March, where beach strandings of this species can number in the hundreds. [3] A. gigantea are found most often in waters that range from 13.1-23.2 °C. [2] The species has not yet been assessed by the IUCN, and thus its conservation status remains unknown. [1]

Description

A. gigantea are known to be able to grow up to 60 cm long, making it one of the largest species of sea hare in Australia. [2] They are usually a dark brown or black color. Additionally, they are distinguished by large paradopia on their backs, which function as limbs allowing the sea hare to swim for short periods of time. [2] The species also has scent and taste receptors known as rhinophores, located on the upper side of its head. [4] These organs resemble a hare's ears and are responsible for its more colloquial name of sea hare. The sea hare's eyes are also located beneath the rhinosphores, and are able to sense light and shadow. [3] Its gills, as well as an internal, calcified shell are located near the organism's heart. [4] The shell itself is particularly fragile, and the paradopia serve a secondary function in both enclosing and protecting it. [4] The adults of this species are also herbivorous in nature, with a diet that primarily consists of algae. [1]

Defense

A. gigantea is able to produce ink and secretions from two main secretory glands that render it hidden or toxic to predators. [5] When ingested by domestic dogs, several symptoms have been recorded, including respiratory issues, ptyalism, emesis, ataxia, and hyperaesthesia. [4] It is suggested the diet of A. gigantea, consisting of organisms such as red algae, provides the molecules needed to create toxins. [2]

Reproduction

A. gigantea mate during summer and early autumn. [2] A. gigantea are hermaphrodites and often mate in numbers ranging from 2 to approximately 20, producing orange colored spawn. [2] In these mating groups, one individual will utilize only female or male reproductive organs respectively, while other participants use both. [2] The eggs produced by A. gigantea are in long and stringy clumps, and hatch into planktonic larvae which feed on microscopic algae. [3]

Related Research Articles

Nudibranch order of molluscs

Nudibranchs are a group of soft-bodied, marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown," "marigold," "splendid," "dancer," "dragon," or "sea rabbit." Currently, about 3,000 valid species of nudibranchs are known.

California sea hare species of mollusc

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.

Anaspidea suborder of molluscs

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.

Sea slug group of marine invertebrates with varying levels of resemblance to terrestrial slugs

Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are actually gastropods, i.e. they are sea snails that over evolutionary time have either completely lost their shells, or have seemingly lost their shells due to having a greatly reduced or internal shell. The name "sea slug" is most often applied to nudibranchs, as well as to a paraphyletic set of other marine gastropods without obvious shells.

Opisthobranchia infraclass of molluscs

Opisthobranchs is now an informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping.

Aplysiidae family of molluscs

Aplysiidae is the only family in the superfamily Aplysioidea, within the clade Anaspidea. 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.

<i>Aplysia</i> genus of molluscs

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.

Sacoglossa order of molluscs

Sacoglossa, commonly known as the sacoglossans or the "sap-sucking sea slugs", are a clade of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia. Sacoglossans live by ingesting the cellular contents of algae, hence the adjective "sap-sucking".

Cyanotoxin Toxins produced by bacteria

Cyanotoxins are toxins produced by bacteria called cyanobacteria. Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under high concentration of phosphorus conditions, they reproduce exponentially to form blooms. Blooming cyanobacteria can produce cyanotoxins in such concentrations that they poison and even kill animals and humans. Cyanotoxins can also accumulate in other animals such as fish and shellfish, and cause poisonings such as shellfish poisoning.

<i>Glaucus atlanticus</i> Species of mollusc

Glaucus atlanticus is a species of small, blue sea slug, a pelagic aeolid nudibranch, a shell-less gastropod mollusk in the family Glaucidae.

Rhinophore

A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs (Nudibranchia), Sea Hares, (Aplysiomorpha) and sap-sucking sea slugs (Sacoglossa).

<i>Aplysia fasciata</i> species of mollusc

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 mollusc

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 punctata</i> species of mollusc

Aplysia punctata is a species of sea slug in the family Aplysiidae, the sea hares. It reaches a length of up to 20 cm (7.9 in) and is found in the northeast Atlantic, ranging from Greenland and Norway to the Mediterranean Sea.

<i>Aplysia vaccaria</i> species of mollusc

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.

William B. Rudman, usually known as Bill Rudman, is a malacologist from New Zealand and Australia. In particular he studies sea slugs, opisthobranch gastropod molluscs, and has named many species of nudibranchs.

<i>Chromodoris orientalis</i> species of mollusc

Chromodoris orientalis is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae. Sea slugs are generally very beautifully colored organisms with intense patterns and ranging in sizes. The Chromodoris orientalis specifically is a white sea slug with black spots in no particular pattern with a yellow, orange, or brown in color ring around its whole body and on its gills. There is much discussion on where it is found, what it eats, how it defends itself without a shell, and its reproduction methods. This is all sought after information because there is not much known about these animals.

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.

Opaline gland

Sea hares are gastropods without hard shells, using their specialized ink as their main defensive mechanism instead. Their ink has several purposes, most of which have a chemical basis. For one, the ink serves to cloud the predator's vision as well as halt their senses temporarily. In addition, the chemicals in the ink mimic food. Their skin and digestive tract are toxic to predators as well. They are also seen to change their feeding behaviours in response to averse stimuli.

Aplysioviolin chemical compound

Aplysioviolin is a purple-colored molecule secreted by sea hares of the genera Aplysia and Dolabella to deter predators. Aplysioviolin is a chemodeterrent, serving to dispel predators on olfactory and gustatory levels as well as by temporarily blinding predators with the molecule's dark color. Aplysioviolin is an important component of secreted ink and is strongly implicated in the sea hares' predatory escape mechanism. While the ink mixture as a whole may produce dangerous hydrogen peroxide and is relatively acidic, the aplysioviolin component alone has not been shown to produce human toxicity.

References

  1. 1 2 3 Wells, Fred E. (January 1986). "A redescription of the sea hare Aplysia gigantea Sowerby, 1869". Journal of the Malacological Society of Australia. 7 (3–4): 173–178. doi:10.1080/00852988.1986.10673985. ISSN   0085-2988.
  2. 1 2 3 4 5 6 7 8 9 10 jurisdiction=New South Wales; corporateName=Australian Museum; author=Rudman, W. B. (2006-01-09). "The Sea Slug Forum - Home". www.seaslugforum.net. Retrieved 2020-04-13.CS1 maint: multiple names: authors list (link)
  3. 1 2 3 4 Bebbington, Alan (2010-07-08). "Aplysiid species from Eastern Australia with notes on the Pacific Ocean Aplysiomorpha (Gastropoda, Opisthobranchia)". The Transactions of the Zoological Society of London. 34 (1): 87–147. doi:10.1111/j.1096-3642.1977.tb00373.x. ISSN   0084-5620.
  4. 1 2 3 4 5 6 Peacock, RE; Hosgood, G; Swindells, KL; Smart, L (2013-06-20). "Aplysia giganteatoxicosis in 72 dogs in Western Australia". Australian Veterinary Journal. 91 (7): 292–295. doi:10.1111/avj.12074. ISSN   0005-0423.
  5. ↑ Moroz, Leonid L. (January 2011). "Aplysia". Current Biology. 21 (2): R60–R61. doi:10.1016/j.cub.2010.11.028. ISSN   0960-9822. PMC   4024469 .
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