''Halgerda onna'' is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

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 ...

, a dorid

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 mat ...

, 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

mollusk 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 es ...

s in the family

Discodorididae Discodorididae is a taxonomic family of sea slugs, specifically dorid nudibranchs, marine gastropod mollusks in the superfamily Doridoidea.Bouchet, P. (2011). Discodorididae. Accessed through: World Register of Marine Species at http://www.ma ...

.Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . ISSN 0076-2997. 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278

Distribution

This species was described from Onna Village,

Okinawa is a prefecture of Japan. Okinawa Prefecture is the southernmost and westernmost prefecture of Japan, has a population of 1,457,162 (as of 2 February 2020) and a geographic area of 2,281 km2 (880 sq mi). Naha is the capital and largest city ...

.''Halgerda onna'' on the Okinawa Slug Site, R.F. Bolland
/ref> It is also reported from

Guam Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic ce ...

.Rudman, W.B., 2001 (October 10) ''Halgerda onna'' Fahey & Gosliner, 2001. n">Rudman, W.B., 2001 (October 10) ''Halgerda onna'' Fahey & Gosliner, 2001. [In
/nowiki> Sea Slug Forum. Australian Museum, Sydney./ref>

References

{{Taxonbar">from=Q5642003 Discodorididae Gastropods described in 2001