''Hypselodoris rosans'' 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), ...

of colourful

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 ...

or 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 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 Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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.� ...

Distribution

This species was described from Ile aux Fouquets,

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

. This species has not been reported by subsequent authors. Animals reported from

Réunion Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the isl ...

and

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

as '' Chromodoris bullocki'' are possibly this species in view of the revision of the ''Hypselodoris bullocki'' clade in 2018.Epstein, H. E.; Hallas, J. M.; Johnson, R. F.; Lopez, A.; Gosliner, T. M. (2018)
Reading between the lines: revealing cryptic species diversity and colour patterns in ''Hypselodoris'' nudibranchs (Mollusca: Heterobranchia: Chromodorididae).
Zoological Journal of the Linnean Society. 2018, XX, 1–74. With 40 figures.Bidgrain, P., 2018

South-west Indian Ocean Seaslug site, accessed 2018-01-20.

Description

Bergh suggests a possible synonymy with ''Chromodoris bullocki'' and quotes Moebius' description as follows (translated from German) "bright rose-red on the back, the mantle with snow-white margin; the rhinophores saffron yellow with scarlet margins of the leaves; the (9) gill leaves on the ground saffron yellow, otherwise scarlet red; the back of the tail bluish red ".

References

{{Taxonbar, from=Q5961664 Chromodorididae Gastropods described in 1889