Libinia emarginata

Libinia emarginata
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Family:	Epialtidae
Genus:	Libinia
Species:	L. emarginata
Binomial name
Libinia emarginata Leach, 1815
Synonyms
Libinia canaliculata Say, 1817

Libinia canaliculata Say, 1817

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 ft (49 m), with exceptional records of up to 400 ft (120 m).

Libinia emarginata is roughly triangular in outline and very heavily calcified, with a carapace about 4 in (100 mm) long and a leg span of 12 inches (300 mm). The whole crab is khaki, and the carapace is covered in spines and tubercles, and, as with other decorator crabs, often clothes itself in debris and small invertebrates.

Mating takes place, and eggs are produced from June to September. The eggs are initially a bright orange-red, but turn brown during development, which takes around 25 days. The eggs then hatch as zoea larvae, and the female can produce another brood of eggs within 12 hours, unlike many other crab species whose females only mate immediately after molting.

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. Also, the rostrum of L. dubia is more deeply forked than that of L. emarginata.

Libinia emarginata lives on various substrates, at depths of up to 150 ft (46 m). Adults are sluggish and not aggressive, and younger crabs are frequently covered with sponges and hydroids.

...
Wikipedia