Relevant Synonyms Crepidula calyptraeiformis Deshayes, 1830 Misidentification -  photo: S. Gofas / Coll. H. Zibrowius

SHORT DESCRIPTION Shell depressed, ovate, rather thin, with distinctly curled apex at posterior margin, then slighly curled dextrally. Outer surface with irregular spiral threads and a scaly periostracum. Inside with a thin septum which covers roughly the posterior half of the shell. color : greyish to buff with three blurred, dark brown spiral bands, not very distinct on the outer surface, vivid inside; septum white. common size : 20-30 mm. DISTINGUISHING CHARACTERISTICS This species is distinguished from C. fornicata by being more depressed, having a more distinctly curled apex, having an external sculpture and having a color pattern of bands rather than blotches. Some native forms known as C. gibbosa Defrance, 1818, which may be forms of the common Mediterranean C. unguiformis Lamarck, 1822 living on a convex substrate, may resemble this species but are smaller and lack the brown bands and spiral sculpture on the outside. This species has been first recorded in the Mediterranean as Crepidula calyptraeiformis, but we follow the advice of Dr. G. Pastorino (of Museo Argentino de Ciencias Naturales, Buenos Aires) in considering this as a synonym of C. aculeata. BIOLOGY / ECOLOGY Specimens from the Pacific Ocean have been reported with large eggs and no pelagic larval stage (Ishiki, 1936). This species does not form stacks as does C. fornicata. habitat : on rock substrates in shallow water.

1st Mediterranean record Alicante harbour, Spain, 1992 [1973]. DISTRIBUTION Worldwide: nearly cosmopolitan in tropics and subtropics: Japan, Hawaii, New Zealand, Western America from California to Chile, eastern America from southeastern United States to Rio de la Plata, and southern Africa. Mediterranean: only known from Alicante, Spain, as Crepidula calyptraeiformis, in the harbour basin used by the fishing fleet, where it is abundant, collected in 1973 by Alfonso A. Ramos-Esplà (Zibrowius, 1992). ESTABLISHMENT SUCCESS Very local but persistent: the population in Alicante was still sustained in 1998. speculated reasons for success : - MODE OF INTRODUCTION Probably through navigation. IMPORTANCE TO HUMANS None.

KEY REFERENCES Hoagland K.E., 1977. Systematic review of fossil and recent Crepidula and discussion of evolution of the Calyptraeidae. Malacologia, 16(2): 353-420. Ishiki H., 1936. Sex changes in the slipper limpets, Crepidula aculeata and Crepidula walshi. Journal of Science, Hiroshima University, ser. B1, 4: 91-99. Zibrowius H., 1992. Ongoing modifications of the Mediterranean marine fauna and flora by the establishment of exotic species. Mésogée, 51: 83-107.   FEEDBACK / COMMENTS TO AUTHORS

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