| Summary: | Crustaceans are a key component of the fauna living in rhodoliths, but patterns in their distribution and abundance remain largely unknown. This paper assessed spatio-temporal variability of Brachyura associated with rhodoliths. A seasonal study was conducted at three depth layers (18, 25, and 40 m), throughout two years (December 2015 to October 2017) at Gran Canaria Island (eastern Atlantic Ocean). A total of 765 crabs belonging to 10 species were collected. A larger abundance and richness of crabs at 25 m correlated with a larger biomass of epiphytic algae attached to rhodoliths. A seasonal pattern was also observed, where a higher richness of crabs occurred in the summer. The Xanthid crab, <i>Nanocassiope melanodactylus,</i> dominated the assemblage (83%); juveniles of this species were more abundant in deeper waters (40 m), while adults were more abundant on the shallower depth layers (18 m and 25 m). The species <i>Pilmunus</i> <i>hirtellus</i> was restricted to 25 m. Nevertheless, <i>Pisa carinimana</i> and <i>Achaeus</i> <i>cranchii</i> did not show any spatio-temporal pattern. In summary, this study demonstrated that two conspicuous crabs, <i>N. melanodactylus</i> and <i>P. hirtellus</i>, associated with rhodolith beds are bathymetrically segregated.
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