Clibanarius erythropus is a species of hermit crab that lives in rockpools and sublittoral waters. It is found in the Mediterranean Sea, Black Sea and eastern Atlantic Ocean from the Azores to Brittany, the Channel Islands and as far north as the south Cornwall coast. Individuals may grow up to a carapace length of 15 millimetres (0.6 in).
A variety of different gastropod shells are used by C. erythropus, the most frequent being Littorina striata, Mitra, Nassarius incrassatus and Stramonita haemastoma, which collectively account for 85% of all the individuals studied in the Azores; in the Mediterranean, shells of Cerithium, Alvania montagui and Pisania maculosa are most used by C. erythropus.
Like other hermit crabs, C. erythropus feeds on "organic debris, decayed and fresh macro-algae with associated fauna and epiphytic algal flora, small invertebrates, and macroscopic pieces of dead and live animal tissues". It has been shown that C. erythropus individuals select substrates where they can cover large distances, and that globose shells allow them greater mobility than elongate ones.
In 2016 the BBC Springwatch programme highlighted C. erythropus and ran a competition to provide a vernacular name. The winning name was St Piran's crab, a process supported by National Trust West Cornwall and the Cornwall Wildlife Trust. St Piran is generally regarded as the patron saint of Cornwall, and was a hermit who survived being thrown into the sea.
- Michael Türkay (2009). Patsy McLaughlin, ed. "Clibanarius erythropus (Latreille, 1818)". World Paguroidea database. World Register of Marine Species. Retrieved 8 June 2010.
- E. Wilson (2005). "A hermit crab — Clibanarius erythropus". Marine Life Information Network.
- Chiara Benvenuto, Gianfranco Sartoni and Francesca Gherardi (2003). "Foraging behaviour of the hermit crab Clibanarius erythropus in a Mediterranean shore". Journal of the Marine Biological Association of the United Kingdom. 83 (3): 457–461. doi:10.1017/S0025315403007331h.
- "Rare hermit crab rediscovered". Cornwall Wildlife Trust. Retrieved 16 March 2016.
- Andrea Z. Botelho & Ana C. Costa (2000). "Shell occupancy of the intertidal hermit crab Clibanarius erythropus (Decapoda, Diogenidae) on São Miguel (Azores)". Hydrobiologia. 440 (1/3): 111–117. doi:10.1023/A:1004190220509.
- Chiara Benvenuto & Francesca Gherardi (2001). "Population structure and shell use in the hermit crab, Clibanarius erythropus: a comparison between Mediterranean and Atlantic shores". Journal of the Marine Biological Association of the United Kingdom. 81 (1): 77–84. doi:10.1017/S0025315401003423.
- http://ntwestcornwall.co.uk/?p=2292 the Incredible Life of a Rockpool