Carapace surface smooth and about 1 ½ times as wide as long in males, less in females; medially convex with central longitudinal crest; anterior margins undulated and expanded almost as far forward as rostrum which broadens distally. Eyestalk cone-shaped with small cornea. Antennal scale leaf-like. Chelipeds unequal in size, smooth, and with short setae on inner margins of fingers. Walking legs much compressed with sharp dorsal margins; dactyl short with ventral movable spines and sharp, curved claw. Abdomen of female wider than that of male.
Carapace: male 65 x 90 mm, female 68 x 87 mm.
Carapace with unusually broad range of colour; small individuals are often white or pale brown, and males of any size may be scarlet. Otherwise combinations of all shades of orange, pink, red-brown, green, grey purple and white occur. One colour may predominate or there may be a mixture with spots, streaks, or a pattern of finely etched, usually symmetrical, lines. Appendages and ventral surfaces mostly white. Chelipeds and walking legs usually have tinges of tan or brown. Eyestalk white; cornea black. Antennal flagellum banded in light and dark brown.
Intertidal. Especially on wave-washed, seaweed-covered rocks in sheltered crevices, where rock surfaces are covered with colourful growths among which the crabs blend. The tendency to remain motionless also helps them to survive predation. Feed on calcareous algae, Corallina, Calliarthron and Bossiella.
Sitka, Alaska, to Point Loma, California; intertidal to 17 m.
Distribution In British Columbia
Common in cold-water areas of British Columbia, but I have no records from the Strait of Georgia.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2023-09-23 4:44:21 AM]
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