Атлант мұхитының тоғыз тікенді шабақ құбыжығы

Species of crustacean

Libinia emarginata, the portly spider crab, common spider crab or nine spined spider crab, is a species of stenohaline crab that lives on the Atlantic coast of North America.

Libinia emarginata occurs from Nova Scotia to the Florida Keys and through the Gulf of Mexico. It lives at depths of up to 160 feet (49 m), with exceptional records of up to 400 feet (122 m). and, as with other decorator crabs, often clothes itself in debris and small invertebrates.

Libinia emarginata is very similar to Libinia dubia with which it is largely sympatric. They can be told apart by examining the row of spines along the center of the carapace: in L. emarginata there are nine, while in L. dubia there are only six.

Libinia emarginata lives on various substrates, at depths of up to 150 feet (46 m). Adults are sluggish and not aggressive, and younger crabs are frequently covered with sponges and hydroids. Unusually for crabs, L. emarginata preferentially walks forwards, rather than sideways, although they are also capable of sidelong movement. Its skeletal, muscular more closely resembles that of forward walking species, rather than that of more closely related sideways walking species. L. emarginata will mate in large aggregations. These aggregations may function as a protective mechanism during reproduction. Males of L. emarginata show an unusual "obstetrical behavior", in which gravid females who are about to release their larvae are held behind the male and aggressively protected.