''Phyllidia varicosa'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

, a dorid

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs, belonging to the order Nudibranchia, that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have b ...

, a shell-less marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the family

Phyllidiidae Phyllidiidae is a family (biology), family of sea slugs, dorid nudibranchs, marine (ocean), marine gastropod mollusks in the superfamily Phyllidioidea. This family is within the clade Doridacea (according to the Taxonomy of the Gastropoda (Bouch ...

.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 Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

s including the central Pacific and the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

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 (biology), class Holothuroidea ( ). They are benthic marine animals found on the sea floor worldwide, and the number of known holothuroid species worldwide is about 1,786, with the greatest number be ...

, ''

Pearsonothuria graeffei ''Pearsonothuria'' is a genus of sea cucumbers in the Family (biology), family Holothuriidae. ''Pearsonothuria graeffei'' is the only species in the genus. Graeffe's sea cucumber is found in the tropical Indo-Pacific Ocean and the Type locality ( ...

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

predators Predation is a biological interaction in which 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 ...

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, bacteria, bacterium, or plant, as well as the effect o ...

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. In the simples ...

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