The Japanese pygmy seahorse (''Hippocampus japapigu'') is a Japanese species of

seahorse A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine fish in the genus ''Hippocampus''. "Hippocampus" comes from the Ancient Greek (), itself from () meaning "horse" and () meaning "sea monster" or " ...

in the family

Syngnathidae The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons (''Phycodurus'' and '' Phyllopteryx''). The name is derived from grc, σύν (), meaning "together", and (), meaning "jaw". The fused jaw is one of the t ...

. It is also sometimes known as the Japan pig.

Distribution and habitat

It lives in Northwestern Pacific near Japan, and lives at depths from 5 to 22 meters, but its usually found at 10 to 13 meters, but does not live with any specific

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 ...

to host, and instead clings onto algal turfs in subtropical reefs. , ''H. japapigu'' is only known to be found in Japan, including Kashiwa-jima Island, Sukumo Bay;

Kushimoto 270px, Shionomisaki Southernmost Point Park is a coastal town located in Higashimuro District, Wakayama Prefecture, Japan. , the town had an estimated population of 15,192 in 8354 households and a population density of 110 persons per km2. The ...

Kii Peninsula The is the largest peninsula on the island of Honshū in Japan. It is named after the ancient Kii Province. Overview The area south of the “ Central Tectonic Line” is called , and is home to reef-like coral communities which are among ...

; Osezaki, Izu Peninsula; the Izu Islands of Miyake and Hachijo;

Sagami Bay lies south of Kanagawa Prefecture in Honshu, central Japan, contained within the scope of the Miura Peninsula, in Kanagawa, to the east, the Izu Peninsula, in Shizuoka Prefecture, to the west, and the Shōnan coastline to the north, while th ...

; and

Chichi-jima , native_name_link = , image_caption = Map of Chichijima, Anijima and Otoutojima , image_size = , pushpin_map = Japan complete , pushpin_label = Chichijima , pushpin_label_position = , pushpin_map_alt = , ...

Ogasawara Islands The Bonin Islands, also known as the , are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan and northwest of Guam. The name "Bonin Islands" comes from the Japanese word ''bunin'' (an archaic readi ...

. The type locality was collected off Imasaki, Okago, Hachijo-jima Island, Izu Islands at a depth of .

Description and feeding

It reaches a length of 1.6 cm, and contains 28 tail rings, 14 dorsal fin rays, 9 pectoral fin rays, and 4 subdorsal rings. It is the size of a jellybean, and its coloration is made for hiding in algae-covered reefs, clinging to soft corals while feeding on

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

. It has a pair of wing-like

protrusion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

s on its neck; unlike other species, it contains only one pair instead of two, and is the only seahorse in the world known to have a bony ridge running down its back.

Taxonomic history

In 2013, after completing his PhD on the biology of the Bargibant's and Denise's pygmy seahorses, Richard Smith went to a fish biology conference in Okinawa in 2013, after which he photographed the Japanese pygmy seahorse on several dives off of Hachijo-jima, one of the Izu Islands about 180 miles from Tokyo. There he found about a dozen specimens. The

species description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

was published by Short and colleagues in a 2018 issue of ''

ZooKeys ''ZooKeys'' is a peer-reviewed open access scientific journal covering zoological taxonomy, phylogeny, and biogeography. It was established in 2008 and the editor-in-chief is Terry Erwin (Smithsonian Institution). It is published by Pensoft P ...

''; it was based on one female

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

, a male and a female

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...

, and two photographs of additional specimens. The holotype and one paratype were deposited at the

Burke Museum The Burke Museum of Natural History and Culture (Burke Museum) is a natural history museum in Seattle, Washington, in the United States. Established in 1899 as the Washington State Museum, it traces its origins to a high school naturalist club fo ...

at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattl ...

; the other paratype was deposited at the

Kagoshima University , abbreviated to , is a Japanese national university located in Kagoshima, Kagoshima Prefecture, Japan. History The university was established in 1949 consolidating the following schools because of educational reform in occupied Japan. * - e ...

Museum. Short and colleagues proposed ''Japanese pygmy seahorse'' as the English and Japanese

common names In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contra ...

for the species. The specific epithet comes from its colloquial Japanese name: Japan Pig or Japapigu.

References

{{Taxonbar, from=Q56034064 japapigu Fish of Japan Endemic fauna of Japan Taxa named by Graham Short Taxa named by Richard Smith Taxa named by Hiroyuki Motomura Taxa named by Healy Hamilton Taxa named by David Harasti Japanese pygmy seahorse