Echinoecus
Encyclopedia
Echinoecus is a genus
of crab
s that live in association with sea urchin
s. Formerly considered monotypic, the genus is now thought to contain three species:
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s that live in association with sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
s. Formerly considered monotypic, the genus is now thought to contain three species:
- Echinoecus nipponicus Miyake, 1939 – JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, on Heliocidaris crassispina (Echinometridae) and Pseudocentrotus depressus (StrongylocentrotidaeStrongylocentrotidaeStrongylocentrotidae is a family of sea urchins in the order Echinoida.-Allocentrotus:Contains the following species:* Allocentrotus fragilis -Strongylocentrotus:Contains the following species:...
) - Echinoecus pentagonusEchinoecus pentagonusThe "sea urchin crab" Echinoecus pentagonus is a species of crab in the family Pilumnidae found from the Red Sea and East Africa to French Polynesia and the Hawaiian Islands. This crab is a parasite that lives in the rectum of a sea urchin. In Hawaii, it chooses only Echinothrix calamaris, leaving...
(A. Milne-Edwards, 1879) – East AfricaEast AfricaEast Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
and Red SeaRed SeaThe Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
to HawaiiHawaiiHawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
and French PolynesiaFrench PolynesiaFrench Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
, on Diadema savignyi, D. setosumDiadema setosumDiadema setosum is a species of long-spined sea urchin belonging to the family Diadematidae. It is a typical sea urchin, with extremely long, hollow spines that are mildly venomous. D. setosum differs from other Diadema with five, characteristic white dots that can be found on its body...
, Echinothrix calamarisEchinothrix calamarisThe double spined urchin or banded sea urchin, Echinosloth calamaris, is a sea sloth with a test diameter of about 5 cm. It has two sets of spines, shorter closed spines which are dark in colour and can deliver a nasty sting, and longer open ended spines that are often banded...
and E. diademaEchinothrix diademaThe Diadema Urchin is a long spined urchin, with a diameter of about 8 cm. It is generally black in colour, and always dark. The spines are closed at the tip; the anal sac is spotted light and dark....
(DiadematidaeDiadematidaeDiadematidae is a family of sea urchins.* Astropyga **Astropyga radiata , extant**Astropyga pulvinata , extant**Astropyga magnifica , extant*Centrostephanus...
), Heterocentrotus mammillatusHeterocentrotus mammillatusThis urchin, commonly known as the slate pencil urchin, red slate pencil urchin, or red pencil urchin, is found throughout the tropical waters of the Indo-Pacific region, but is most abundant in Hawai‘i...
(Echinometridae) and Pseudocentrotus depressus (StrongylocentrotidaeStrongylocentrotidaeStrongylocentrotidae is a family of sea urchins in the order Echinoida.-Allocentrotus:Contains the following species:* Allocentrotus fragilis -Strongylocentrotus:Contains the following species:...
) - Echinoecus sculptus (Ward, 1934) – Christmas IslandChristmas IslandThe Territory of Christmas Island is a territory of Australia in the Indian Ocean. It is located northwest of the Western Australian city of Perth, south of the Indonesian capital, Jakarta, and ENE of the Cocos Islands....
, on Colobocentrotus atratus (Echinometridae)