RELATIONSHIPS BETWEEN PATELLA-FERRUGINEA GMELIN, 1791 AND THE OTHER TYRRHENIAN SPECIES OF PATELLA (GASTROPODA, PATELLIDAE)

The external morphology of soft parts of the rare Patella ferruginea G melin, 1791 is described, and its relationships with P. caerulea, P. r ustica and P. ulyssiponensis are investigated on both morphological an d electrophoretic grounds. Soft part morphology is a good discriminati ve tool, but of little help in detecting affinities. Electrophoretic d ata on 19 presumptive loci suggest that P. rustica is the closest spec ies to P. ferruginea, whereas P. caerulea and P. ulyssiponensis are cl ustered separately. Mean observed heterozygosities are higher in P. fe rruginea and P. rustica. It is concluded that in case of subdivision o f the genus Patella L., 1758, P. ferruginea and P. rustica should be p laced together in the subgenus Patellastra Monterosato, 1884.