''Phyllidia varicosa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sea slug 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 gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary t ...

, a dorid nudibranch, a shell-less

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family

Phyllidiidae Phyllidiidae is a family of sea slugs, dorid nudibranchs, marine gastropod mollusks in the superfamily Phyllidioidea. This family is within the clade Doridacea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). Distributi ...

.Bouchet, P. (2015)
''Phyllidia varicosa'' Lamarck, 1801.
In: MolluscaBase (2015). Accessed through: World Register of Marine Species on 2016-11-15.

Distribution

This species is widely distributed throughout the Indo-West

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

s including the central Pacific and the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

Description

This is a large species growing to at least 115 mm. It can be distinguished by its numerous (3 to 6), longitudinal, tuberculate notal ridges. The ridge and bases of the tubercles are a blue-grey colour. The tubercles are capped in yellow. The foot sole has a black longitudinal foot stripe. The rhinophoral clavus possesses 27 to 30 lamellae.Rudman, W.B., 1999 (January 12
''Phyllidia varicosa'' Lamarck, 1801.
n/nowiki> Sea Slug Forum. Australian Museum, Sydney.

Mimicry

Juveniles of the

sea cucumber Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothuria ...

, '' Pearsonothuria graeffei'' are brightly coloured and closely resemble ''Phyllidia varicosa''. They are white and blue or black, with a few large, yellow, thorn-like projections. These bright colours warn

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

of the

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

of the nudibranch, and this

mimicry In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...

on the part of the sea cucumber species serves to protect it also. The adult sea cucumber has much duller colouration, but it is also much larger than the sea slug and has its own toxic chemicals at this stage.Invertebrate of the month: ''Pearsonothuria graeffei''
Florida Museum of Natural History. Retrieved 2012-02-16.

References

External links

* * * Erwin Koehler (2016

Philippine Sea Slugs, accessed 2016-11-15. * {{Taxonbar, from=Q1118097 Phyllidiidae Gastropods described in 1801 Taxa named by Jean-Baptiste Lamarck