''Goniobranchus setoensis'' 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 ''Doridacea'' is a taxonomic grouping of dorid nudibranchs, shell-less marine gastropod mollusks.Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005''Classification and nomenclator of gastropod families ...

nudibranch 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 matc ...

, a marine

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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Chromodorididae Chromodorididae, or chromodorids, are a taxonomic family of colourful, sea slugs; dorid nudibranchs, marine gastropod mollusks in the superfamily Doridoidea. “Chromodorid nudibranchs are among the most gorgeously coloured of all animals.” ...

''.

Taxonomic history

This species was known as ''Chromodoris setoensis'' for many years before it was transferred to the genus '' Goniobranchus'' on the basis of molecular (DNA) evidence in 2012.Johnson R.F. & Gosliner T.M. (2012
''Traditional taxonomic groupings mask evolutionary history: A molecular phylogeny and new classification of the chromodorid nudibranchs.''
PLoS ONE 7(4): e33479.

Distribution

This species was described from

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. It has been confused with '' Goniobranchus decorus'' and many records of ''G. decorus'' are in fact misidentifications. It occurs in the central Indo-Pacific region from Japan to Sri Lanka, and as far east as the Marshall Islands and Kiribati. The two species are

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

in the Marshall Islands.Scott Johnson, 2015
''Goniobranchus decorus'' (Pease, 1860).
n/nowiki> Underwater Kwajalein.

Description

The body of this chromodorid nudibranch is translucent white with opaque white lines, purple spots and a sub-surface margin of orange-red. There is usually a white line around the centre of the back and a line running from between the

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, sea har ...

s to the middle of the back where it divides to pass around the gills in a loop. Outside the outer white line is a row or double row of purple spots which never have a halo of white around them. There are small white spots along the mantle edge. The tips of the

s and the outer part of the gills is white.Rudman, W.B., 2007 (September 13
''Chromodoris decora'' (Pease, 1860).
n/nowiki> Sea Slug Forum. Australian Museum, Sydney. (Description includes both ''G. decorus'' and ''G. setoensis'')

Ecology

''Goniobranchus setoensis'' feeds on

sponges Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through ...

of the family Aplysillidae.

References

{{Taxonbar, from=Q13645404 Chromodorididae Gastropods described in 1938