Carapace surface slightly rugose; male more than twice as wide as long, female about 1 ½ times as wide as long; margins faintly scalloped; a median dorsal ridge and small knobs and elevations laterally. Rostrum sub-rectangular but narrowing distally and sloping downwards. Chelipeds unequal in size; hand broad and flattened, with many knobs and ridges. Abdomen only slightly asymmetrical and with small plates which have upturned edges. Antennal scales leaf-like. Eyestalk cone-shaped; cornea small. Capitate setae on appendages and ventral surfaces produce a somewhat velvet-like surface.
Carapace: male 41 x 75 mm, female 49 x 80 mm.
Carapace varies greatly; small individuals are usually white but larger ones have a tremendous range of colour, mostly brilliant. One colour may predominate or may be combined with others in mottled, streaked or pebbled patterns. Chelipeds and walking legs usually brown with white dorsal margins. Antennal flagellum usually banded in dark and light brown. Ventral surfaces light coloured with a few streaks or spots of bright colour.
Subtidal or rarely low intertidal; in crevices or the base of eelgrass on rocky areas well hidden by seaweed. They blend well into the uneven, encrusted rocky habitat and do not move until touched. They eat calcareous algae as well as encrusting animals.
Amchitka Island, Alaska, to Santa Rosa Island, California (34°01’15” - 45’5”N, 120°00’14” - 30”W); intertidal to 45 m.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. 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:
18/10/2019 4:01:45 AM]
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