How to Distinguish from Similar Species: The most similar species is Lopholithodes foraminatus, the box crab. L. foraminatus has a large sinus excavated from the carpus of the cheliped so that when viewed from the front it has an obvious "breathing hole" through the chelipeds, while this species does not (picture). L. foraminatus also has spinelike tubercles on the legs and chelipeds instead of blunt, rounded spines as seen on L. mandtii. The color of the two crabs is also distinctive.
Geographical Range: Sitka, Alaska to Monterey, CA
Depth Range: Subtidal to 137 m
Habitat: In rocky areas, especially areas with strong currents. We find it occasionally by SCUBA along Sares Head.
History: Note: DO NOT COLLECT
THIS CRAB! It is uncommon in Puget
Sound/Straits and the
Washington Fish and Wildlife dept. lists it as a protected
Adults come up shallower to breed in late winter and spring.
is one of the largest crabs on the Pacific Coast of the 48
width can be up to 30 cm or more. It feeds on sea urchins and
echinoderms, has been observed eating sea anemones. Chelae
are surprisingly cuplike, and lined with teeth and setae
are a bright orange with
on the carapace,
and may occasionally be found under rocks at extremely low tide.
Dichotomous Keys:Coffin, 1952
Flora and Fairbanks, 1966
General Notes and Observations: Locations, abundances, unusual behaviors, etc.: We find this species from time to time on Sares Head.
Its chelae have teeth and setae along the edges but a cuplike depression in the surface. Photo by Dave Cowles
Note that the antennae have spines. (Note also that this animal is encrusted with barnacles). Photo by Dave Cowles
When this species folds its legs together, which it often does in defense, they fit tightly against the carapace and against each other. Photo by Dave Cowles
Note that the carpus of the chelae does not have a large, obvious sinus that serves as a "breathing hole" when the legs are folded tight against the carapace. Photo by Dave Cowles
There is a very large preserved individual of this species, captured many years ago, on display at the main Walla Walla College campus in the Biology department. Its carapace width is 22 cm. All the color has faded to a flesh tone with a few slightly darker red spots. (Dave Cowles)
The three chela
photos below are of a specimen seen at 18 m depth on Sares Head, June
width 18 cm. The left chela
has strong, molar-like dentitions, while the right chela
is narrower, spoon-shaped, and with narrow dentitions only along the
Authors and Editors of Page:
Dave Cowles (2004): Created original page