E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Hapalogaster mertensii Brandt, 1850
Hairy Crab
Family: Lithodidae

Species account author: Josephine Hart.
Extracted from Crabs and their relatives of British Columbia.
Photo of species

© Aaron Baldwin  Email the photographer   (Photo ID #96980)

E-Fauna BC Static Map
Distribution of Hapalogaster mertensii in British Columbia
Details about map content are available here.

Species Information

Carapace relatively flat with soft capitate setae and elongate clavate setae and stiff bristles on tips of spines. Rostrum narrow, pointed, and longer than orbital. Antero-lateral teeth straight and slender and much longer than orbital. Margin of carapace behind cervical groove cut into long slender teeth decreasing in size posteriorly. Antennal base spiny. Eyestalk long and slender. Inner margin of last 2 segments of 3rd maxilliped distinctly inflated. Right cheliped like that of H. grebnitzkii but usually has 4 longitudinal rows of spines on palm. Dactyl about ¾ length of palm. Walking legs also similar but marginal teeth longer and more slender and with stiff setae near tips of spines. Abdomen with narrow plates on 2nd segment.


Carapace: male 25 x 25 mm, female 22 x 24 mm.


Carapace brown and red, with a few white spots, and covered with pale yellowish tan or dark brown setae and bristles. Tips of fingers of chelipeds orange and teeth white; other surfaces like the carapace. Walking legs with a dark red band and 2 white band on the propodus. Dactyl red-brown and pale brown with black claw. Sternum red. Eyestalk pale brown; cornea black with orange flecks. Flagellum of antenna banded with wide brown sections and narrow translucent ones.


Usually occur under loose rocks, especially when these are covered with seaweeds. The animals are adept at clinging tightly to the undersurface of rocks and squeezing into narrow crevices. Some are parasitized by the rhizochephalan Briarosaccus tennellus which can be seen as an egg-filled sac attached to the ventral abdomen.



Atka, Aleutian Islands, to Puget Sound, Washington; intertidal to 55 m.
Distribution In British Columbia

Widespread in suitable habitats.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. 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: 2024-02-29 7:43:32 AM]
Disclaimer: The information contained in an E-Fauna BC atlas pages is derived from expert sources as cited (with permission) in each section. This information is scientifically based.  E-Fauna BC also acts as a portal to other sites via deep links.  As always, users should refer to the original sources for complete information.  E-Fauna BC is not responsible for the accuracy or completeness of the original information.

© E-Fauna BC 2021: An initiative of the Spatial Data Lab, Department of Geography, UBC