''Rostanga risbeci'', 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 ...

of sea slug, 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, a

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 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 ...

'' Discodorididae''.

Distribution

This species was described from Aitsu, Amakusa, Japan with additional specimens from Sagami Bay and the Echizen coast.Rudman, W.B., 2002 (February 4
''Rostanga risbeci'' Baba, 1991.
n/nowiki> Sea Slug Forum. Australian Museum, Sydney.

Description

''Rostanga risbeci'' is a purple-black or black dorid nudibranch with the dorsum covered with

caryophyllidia Caryophyllidia are an anatomical feature of the external dorsal surface of dorid sea slugs. Caryophyllidia are sensory tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty ou ...

; in general it is very similar in shape, but not in colour, to other species of ''Rostanga''.

Ecology

This nudibranch is reported to feed on the black sponge ''Halichondria okadai'' - family

Halichondriidae Halichondriidae is a family of sea sponges belonging to the order Suberitida. These sponges have a skeleton consisting of dense bundles of spicules occurring in a more or less random pattern. Genera The following genera are recognised in the fam ...

. Most species of ''Rostanga'' feed on sponges of the family Microcionidae.

References

{{Taxonbar, from=Q14287757 Discodorididae Gastropods described in 1991