How to Distinguish from Similar Species:
A similar, somewhat larger crab is the Furrowed Rock Crab (Romaleon branneri
). This species is not common in the intertidal region, unlike M. magister,
and differs in that the dactyls of its chelae have black tips and spines that line the upper margin of the movable finger of the claws. Cancer productus
, often found in the intertidal in the Pacific Northwest, also has black tips to the dactyls of the chelae. Metacarcinus gracilis
has a distinct tooth behind the widest point of the carapace and has no spiny ridges on the carpus, propodus, and dactyl of the chelae.