''Hemicentrotus pulcherrimus'' 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 appropriat ...

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) o ...

, the only one in the monotypic genus ''Hemicentrotus''. It was first described by the American engineer and marine zoologist

Alexander Agassiz Alexander Emmanuel Rodolphe Agassiz (December 17, 1835March 27, 1910), son of Louis Agassiz and stepson of Elizabeth Cabot Agassiz, was an American scientist and engineer. Biography Agassiz was born in Neuchâtel, Switzerland and immigrated to ...

in 1864 as ''Psammechinus pulcherrimus''. Its range extends along the coasts of

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

, and in

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 n ...

from

Kyūshū is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surround ...

to Ishikari Bay. An edible species, it is harvested from Kyūshū to Fukui, in the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, i ...

Description

This sea urchin has a thick

test Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film), ...

and a large number of tiny, fine, sharp spines. The tubercles are small and closely packed, arranged in slightly zig-zag horizontal rows, with four to eight tubercles on each inter-ambulacral plate and three on each ambulacral plate. The pores are arranged in diagonal lines of four, with the rows being separated by small tubercles. The colour of this sea urchin is pale greenish-olive above, and brownish-green below.

Distribution

''H. pulcherrimus'' is native to tropical waters in the western Central Pacific Ocean, the waters around

Palau Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the ...

and the South China Sea. It occurs down to depths of about , but it is mostly found on boulders in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

and in the shallow subtidal zone at depths of less than .

Ecology

The species is herbivorous, grazing on marine algae. It mostly feeds on the red leafy alga ''

Acrosorium polyneurum ''Acrosorium polyneurum'' is a species of red algae first described by Okamura. It grows in intertidal and shallow subtidal waters in Japan where it is grazed by the sea urchin ''Hemicentrotus pulcherrimus ''Hemicentrotus pulcherrimus'' is a ...

'' between December and March at the times of year when it is abundant, and migrating to areas of crustose coralline algae at other times of year when the red alga is scarce. As is the case with other sea urchins, ''H. pulcherrus'' liberates eggs and sperm into the water column and the echinopluteus

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e spend several months drifting with the

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 cruc ...

. They are stimulated to settle on the seabed by the attachment of

diatom A diatom ( Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising se ...

s and by the presence in the water of particles of an alga such as ''

Hizikia fusiformis (''Sargassum fusiforme'', syn. ''Hizikia fusiformis''), sometimes called hiziki, is a brown sea vegetable growing wild on rocky coastlines of East Asia. Hijiki has been a part of the Japanese culinary sphere and diet for centuries. It is rich ...

'' which grows around the coasts of Japan.

Uses

In Japan, ''H. pulcherrus'' has been harvested commercially as a seafood since the 1600s. It is eaten after being preserved with alcohol or brine, since it has a bitter taste when raw.

References

{{Taxonbar, from=Q2409706 Strongylocentrotidae Edible shellfish Taxa named by Ole Theodor Jensen Mortensen