''Romaleon antennarium'' (formerly ''Cancer antennarius''), commonly known as the Pacific, brown or California rock crab, is a

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 ...

of the genus ''

Romaleon ''Romaleon'' is a genus of marine crabs formerly considered in the genus ''Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benig ...

'' found on the western coast of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

Description

''Romaleon antennarium'' has a fan-shaped

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 ...

with eleven teeth to either side of the eyestalks, the widest point falling at the eighth or ninth tooth. The chelipeds are quite stout with the black tips bent downward. The antennae are long and prominent, accounting for the specific name. The dorsal surfaces of adults are uniformly red, but the ventral surface of the carapace is spotted. This species is easily confused with the red rock crab, ''

Cancer productus ''Cancer productus'', one of several species known as red rock crabs, is a crab of the genus ''Cancer'' found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest. Description ''Cancer p ...

''. They can be distinguished by the less prominent antennae, less robust claws, and lack of ventral spots on the latter.

Fishery

''R. antennarium'' is harvested by sport and commercial fishermen in California, mostly from Morro Bay south. The California rock crab fishery is made up of three species - the yellow rock crab ('' C. anthonyi''), the brown rock crab (''R. antennarium''), and the red rock crab ('' C. productus''). Rock crab landings for 1999 were 790,000 pounds and have averaged 1.2 million pounds per year from 1991-1999.

References

Top and Bottom Views of the Rock Crab
- ''Dana Point Fish Company'' {{Taxonbar, from=Q6496948 Cancroidea Crustaceans described in 1856