Cancridae

Family: Cancridae

Group: Marine Invertebrate, Species

Scientific Name	Common Name	Summary
Cancer productus	Red rock crab	This crab is known as the "red rock crab," and is often confused with the Graceful rock crab (Metacarcinus gracilis), and the commercially important Dungeness Crab (Metacarcinus magister). Neither red rock crabs nor Dungeness crabs have the black claw tips of Cancer productus, and when in juvenile form, they do not present the same labyrinthine patterns on the dorsal side. Cancer productus tends to inhabit shallower areas than Dungeness Crab (Metacarcinus magister). Red rock crabs are aggressive predators, pursuing all sorts of invertebrates as well as fighting over dead organisms.
Glebocarcinus oregonensis	Pygmy rock crab	This crab is readily distinguished thanks to its bumpy carapace, its being much less hairy than C. branneri, and its small size.
Metacarcinus gracilis	Graceful rock crab	The graceful rock crab is a common species found primarily on soft bottoms, especially where Eelgrass (Zostera marina) occurs. This species is often mistaken for small specimens of the the related Dungeness Crab (Metacarcinus magister). The graceful rock crab does not have the sharp, toothed ridge as seen the Dungeness Crab (Metacarcinus magister). Also, in the M. magister, the posterior-most carapace spine is also the widest part of the carapace. In M. gracilis there is a tiny spine behind the spine forming the widest point of the carapace (see photo with inset).
Metacarcinus magister	Dungeness Crab	The famous Dungeness crab is Alaska's most profitable crab species. This crab prefers sandy areas and is especially prevalent in eelgrass areas. A related species, the Graceful rock crab (Metacarcinus gracilis) is very similar but smaller and lacks the strongly toothed dorsal margin of the claws seen in the Dungeness.
Romaleon branneri	Furrowed rock crab	Romaleon branneri is not uncommon but easily overlooked in the low intertidal and shallow subtidal. It is the only cancrid crab found in Alaska that has a fuzzy carapace. In southern British Columbia the furrowed rock crab overlaps the range of Romaleon antennarius (Stimpson, 1857). Juveniles of that species have a hairy carapace and could be confused with R. branneri. Look at the upper margin of the claws, in R. branneri this is sharply toothed, while in R. antennarius this ridge is rounded. Romaleon branneri is often found in areas with deep rock piles. Carefully moving these rocks reveals this and many other fascinating, rarely seen species.