Lopholithodes mandtii (Brandt, 1849)
Common name(s): Puget Sound King Crab
|Synonyms: Echinocerus cibarius, Ctenorhinus setimanus|
|Lopholithodes mandtii, about 15 cm across carapace. Caught by SCUBA off Sares Head|
|Photo by Dave Cowles|
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.
Biology/Natural 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 species. Adults come up shallower to breed in late winter and spring. This is one of the largest crabs on the Pacific Coast of the 48 states. Carapace width can be up to 30 cm or more. It feeds on sea urchins and other echinoderms, has been observed eating sea anemones. Chelae are surprisingly cuplike, and lined with teeth and setae (picture). Juveniles are a bright orange with prominent tubercles on the carapace, and may occasionally be found under rocks at extremely low tide.
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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 24, 2005. Carapace 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 margin.
|The right chela (above) is narrower than the left, spoonlike, and has narrow dentitions along the margins. The left chela (right, dactyl and above right, propodus) has large, molar-like dentitions. It appears that the left chela is for crushing and the right is for finer handling and cutting. Note the many setae along the edges of both chelae. These photos are from a large individual, 18 cm carapace width.|
|This very small individual (top and side view above) has a carapace width of only 4.5 cm. Photo by Dave Cowles|
An underwater photo of a juvenile by Kirt Onthank, August 2007