Pagurus prideaux, commonly known as the Prideaux’s hermit crab, is a species belonging to the family Paguridae, within the order Decapoda. Its scientific name honors Charles Prideaux, an English naturalist. This hermit crab inhabits seabeds, especially in sandy and gravelly areas, and is found at depths ranging from the intertidal zone to approximately 90 meters. Its geographical distribution includes mainly the northeastern Atlantic Ocean, from the coasts of Norway to the western Mediterranean, including the North Sea and the British Isles.
Morphologically, Pagurus prideaux has a body length that typically ranges from 3 to 6 cm, although some exceptions may exceed these sizes. Like other hermit crabs, it uses empty gastropod shells to protect its soft abdomen. Its body is asymmetrical, with a pair of chelae or claws, the left of which is usually larger and more robust than the right. Its coloration varies from brown to reddish tones, with some white or pink spots on the legs. A distinctive feature that differentiates it from similar species, such as Pagurus bernhardus, is its symbiotic relationship with the cnidarians Adamsia palliata, a sea anemone that attaches to the shell and is usually absent in the case of Pagurus bernhardus. Additionally, Pagurus prideaux tends to have more robust claws and less uniform coloration.
Regarding its feeding habits, Pagurus prideaux is an omnivorous and opportunistic species, feeding mainly on small benthic invertebrates such as molluscs and annelids, as well as decaying organic matter. It also consumes algae and small suspended organic particles in the water. As a scavenger, this hermit crab plays an important role in the marine ecosystem by helping to clean the seafloor of animal remains.
The reproduction of Pagurus prideaux is sexual and follows a pattern similar to that of other hermit crabs. The mating season typically occurs in spring and summer. After mating, females carry the fertilized eggs attached to their pleopods (swimming appendages) on the ventral side of their abdomen until they hatch. The offspring go through a larval stage, known as zoea, which is pelagic and forms part of the plankton, until they finally develop into juveniles and adopt a benthic lifestyle.
A curious and relevant fact about Pagurus prideaux is its symbiotic relationship with the sea anemone Adamsia palliata, which adheres to the shell the crab uses for shelter. This relationship is a clear example of mutualism, as the anemone benefits by being transported to new locations where it can access more food, while the crab gains additional protection thanks to the anemone’s stinging tentacles, which help deter potential predators. This interaction is so strong that the presence of Adamsia palliata on the shell is an almost certain indicator that the crab is Pagurus prideaux and not another similar species.
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