''Jorunna parva'', commonly known as the sea bunny, is a species of dorid nudibranch, a 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 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 Discodorididae. The species was first described by Kikutaro Baba.Bouchet, P. (2010)
''Jorunna parva'' (Baba, 1938)
World Register of Marine Species. Its resemblance to a

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...

facilitated a surge in popularity on Twitter throughout Japan in 2015.

Description

The species is about 1 cm long on average. Its black-and-white rhinophores somewhat resemble a rabbit's ears. Its external gills are located near its rear. Its body is covered in papillae, fleshy protuberances used for sensory functions, giving it the appearance of a furry animal. There are multiple colorations of ''Jorunna parva'', including yellow, white, and green, though the latter is rarely photographed. All of these variants have black papillae interspersed among papillae of their main color. There is controversy over whether or not the different colorations are divergent species. Like most other members of its genus, ''Jorunna parva'''s diet consists of toxic sponges in the family

Chalinidae Chalinidae is a family of marine demosponges, containing the following genera: * '' Chalinula'' Schmidt, 1868 * '' Cladocroce'' Topsent, 1892 * '' Dendrectilla'' Pulitzer-Finali, 1983 * '' Dendroxea'' Griessinger, 1971 * ''Haliclona ''Haliclon ...

. These sponges contain toxins that can be used for cancer treatments. ''Jorunna parva'' are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

s, meaning they produce both

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

and

egg cell The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is ...

s. They cannot fertilize the eggs themselves.

Distribution

This species was described from Kii Province,

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 ...

. ''Jorunna parva'' has subsequently been reported from the Philippines, Tanzania, Papua New Guinea, Seychelles and

Réunion Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...

but there are some doubts as to whether it is really a species complex. The ''Jorunna parva'' are concentrated in areas where there is an abundance of food and where resources are easily acquired. They often cling to submerged vegetation and spend majority of the time at the bottom of tropical waters.

References

* Camacho-García Y.E. & Gosliner T.M. (2008). ''Systematic revision of Jorunna Bergh, 1876 (Nudibranchia: Discodorididae) with a morphological phylogenetic analysis.'' Journal of Molluscan Studies 74: 143–181 {{Taxonbar, from=Q13373630 Discodorididae Gastropods described in 1938