Glaucus atlanticus

From Wikipedia, the free encyclopedia

This article needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (January 2008)

Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion. (March 2008)

Glaucus atlanticus

Glaucus atlanticus (left) and its close relative Glaucilla marginata (right)

Scientific classification

Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Opisthobranchia
Suborder:	Nudibranchia
Superfamily:	Aeolidioidea
Family:	Glaucidae
Genus:	Glaucus
Species:	G. atlanticus

Binomial name

Glaucus atlanticus
Forster, 1777

Glaucus atlanticus is a species of medium-sized, floating, blue sea slug, a pelagic aeolid nudibranch, a marine opisthobranch gastropod mollusk in the family Glaucidae. It is the only species in the genus Glaucus, but is closely related to Glaucilla marginata, another member of the family Glaucidae.

G. atlanticus has many common names, including: Blue sea slug, Blue ocean slug, Blue dragon and Sea lizard.

1 Description
2 Distribution
3 Habitat
4 Life habits
5 References

[edit] Description

This species typically grows to 6 cm in length. It is dark blue in color.

[edit] Distribution

This nudibranch is pelagic, and is distributed throughout the world's oceans, in temperate and tropical waters.

[edit] Habitat

This species floats upside down on the surface tension of the ocean water.

[edit] Life habits

G. atlanticus preys on other larger pelagic species: the dangerously venomous Portuguese Man o' War Physalia physalis; the by-the-wind-sailor Velella velella; the blue button Porpita porpita; and the violet snail, Janthina janthina. Occasionally Glaucus will feed on others of its kind, a cannibalistic behavior.

G. atlanticus is able to feed on P. physalis due to its immunity to the venomous nematocysts. The blue sea slug will consume the entire organism. After consumption it will select the most venomous nematocysts and use them for defense. G. atlanticus stores the venom in its cnidosacs, specialized sacs on the tip of their cerata, the thin feather-like "fingers" on its body. Because Glaucus stores the venom, it can produce a more powerful and deadly sting than the Man o' War upon which it feeds.

With the aid of a gas-filled sac located in its stomach, G. atlanticus is able to stay afloat at the surface. Due to the location of the gas sac the blue sea slug actually floats upside down. The dorsal surface, actually the foot and underside, has either a blue or blue-white coloration. The true dorsal surface is completely silver-grey. This coloration is an example of counter-shading, which helps protect G. atlanticus from predators from below,sides and above.

Scientists have often argued over whether G. atlanticus moves on its own or depends on the wind for locomotion.

Glaucus is, like most sea slugs, a hermaphrodite, meaning it contains both male and female reproductive organs. After mating, both slugs will produce egg strings.