How to Distinguish from Similar Species:Petrolisthes eriomerus has a cheliped with a longer carpus with parallel margins, its antennal flagellae are greenish, and it has blue on its mouthparts and on the cheliped.
Geographical Range: Queen Charlotte Islands, Canada to Point Conception, CA + northern Channel Islands in CA. Most common in southern part of range.
Depth Range: Upper and middle intertidal
Habitat: Under stones and in mussel beds., especially on the outer coast.
Biology/Natural History: A very common inhabitant of mussel beds in central and northern California. Feeds on plankton and suspended detritus by using the feathery hairs on its maxillipeds, which it waves in the water. Occasionally eats algae or dead animal tissue. Reproduces all year in California, March to July in Puget Sound. Eggs are bright red or maroon when laid, fade to brownish red. The egg clutches of females frequently have multiple male parentage. This seems to give a reproductive advantage under conditions of warm temperature shock (Yokachonis et al., 2020). As with all porcelain crabs, this species will readily drop (autotomize) its claws if grasped by them (probably the source of the name--they break easily like fine china). Unlike P. eriomerus, the claw of this crab stops pinching when dropped. The zoea larvae of porcelain crabs have extremely long spines, especially the rostral spine. This species can often be found in the same areas as P. eriomerus, but this species avoids hiding under rocks that have sand or sediments around them so they are usually higher in the intertidal. They don't generally swim, but if forced to do so they often swim with their ventral side up, flapping their abdomen with their uropods extended for propulsion.
Individuals are often found with puncture wounds on their claws (Rypien et al., 2007). This seems to be due to interspecific competition in the form of "shoving matches". The incidence of injuries is similar for males and females, suggesting the competition may be for space rather than for mates. Injuries are most common on intermediate (not the largest) individuals and in more crowded, wave-exposed sites.
Flora and Fairbanks, 1966
Kozloff 1987, 1996
Smith and Carlton, 1975
Stillman, Jonathon H., John K. Colbourne, Carol E. Lee, Nipam H. Patel, Michelle R. Phillips, David W. Towle, Brian D. Eads, Greg W. Gelembuik, Raymond P. Henry, Eric A. Johnson, Michael E. Pfrender, and Nora B. Terwilliger, 2008. Advances in crustacean genomics. Integrative and Comparative Biology 48:6 pp 852-868
Stillman, Jonathon H., Kristen S. Teranishi, Abderrhamane Tagmount, Erika A. Lindquist, and Peter B. Brokstein, 2006. Construction and characterization of EST libraries from the procelain crab, Petrolisthes cinctipes. Integrative and comparative biology 46:6 919-930 : Characterizing genes which are transcribed in this species under different temperature conditions.
Rypien, Krystal L. and A. Richard Palmer, 2007. The
sex, size and habitat on the incidence of puncture wounds in the claws
of the porcelain crab Petrolisthes cinctipes
J. Crustacean Biology 27:1 59-64
Yockachonis, Thomas, C. Seabird McKeon, Amanda Mm Windsor, and Jonathon H. Stillman, 2020. Multiple paternity in the intertidal zone porcelain crab Petrolisthes cinctipes Randall, 1840 (Decapoda: Anomura: Porcellanidae) is a life-history strategy that increases fitness during heat stress. Journal of Crustacean Biology 40:6 pp 684-691. https://doi.org/10.1093/jcbiol/ruaa071
General Notes and Observations: Locations, abundances, unusual behaviors:
Authors and Editors of Page:
Dave Cowles (2006): Created original page