''Hyas coarctatus'' is a marine

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

species native to the

North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...

. It is characterized by a lyriformed shell.

Morphology

''Hyas coarctatus'' looks like the

great spider crab The great spider crab, ''Hyas araneus'', is a species of crab found in northeast Atlantic waters and the North Sea, usually below the tidal zone. In 1986, two specimens were captured at the South Shetland Islands off the Antarctic Peninsula ...

(''H. araneus'') but has a lyriformed shell. The

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

of a large specimen is up to 60 mm long and 44 mm wide. The colour is grey-brown on the dorsal side, sometimes with a bit reddish, the ventral side is dirty white. The

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

horns of ''H. coarctatus'' are slightly longer and spaced further apart than in ''H. araneus''.

Cheliped A chela ()also called a claw, nipper, or pinceris a pincer-like organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through New Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds. ...

s are longer than in ''H. araneus''. The outer segment of the walking legs is often more or less furry.

Distribution and ecology

''H. coarctatus'' is found at both hard, stony, sandy and soft bottoms from 1 to 500 meters depth, though most often above 50 meters. ''H. araneus'' inhabits shallower depths. ''H. coarctatus'' is widely distributed in the North-East Atlantic and adjacent seas. The northern border is around the north and west coasts of

Spitsbergen Spitsbergen (; formerly known as West Spitsbergen; Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norw ...

and

Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...

, in the south it is found down to the north-east coast of France, and in the east to the Western

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...

, the

Belt Sea Belt may refer to: Apparel * Belt (clothing), a leather or fabric band worn around the waist * Championship belt, a type of trophy used primarily in combat sports * Colored belts, such as a black belt or red belt, worn by martial arts practitio ...

and the Öresund.

References

{{Taxonbar, from=Q3409020 Majoidea Crabs of the Atlantic Ocean Crustaceans described in 1815 Taxa named by William Elford Leach