Butterfly Crab

How to Distinguish from Similar Species: Cryptolothodes sitchensis has a similar carapace but its rostrum is widest at the tip and its chelae are smooth.

Biology/Natural History: Feeds on bryozoans, coralline algae, and other attached species. Usually lives deeper than does C. sitchensis.

Rocky banks, shell rubble near rocky cliffs. Open coast or inland waters, especially in high current areas.

Geographical Range: Amchitka Island, Alaska to Santa Rosa Island, CA. Less common in the southern parts of the range.

Depth Range: Low intertidal to 45 m

This lithodid crab has a carapace that spreads hugely, covering not only the thoracic segments but extending so far out that when the animal is inactive not even the tips of the legs can be seen from above. The rostrum is widest at the base and narrower at the tip. The propodus of its chelipeds are covered with rough tubercles, and its abdominal plates have a raised ridge around the margin. Carapace color is quite variable, from dark gray-blue as here to bright orange, white, or red. The central part of the carapace is often a different color than the "wings". Carapace width to 8 cm.

Cryptolithodes typicus, commonly known as the butterfly crab, is a species of lithodid crustacean native to coastal regions of the northeastern Pacific Ocean, ranging from Amchitka Island, Alaska to Santa Rosa Island, California.