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Introduction
The limpet Patellaferruginea Gmelin, 1791 (Mollusca: Gastropoda) is endemie to the
Western Mediterranean, where it is considered the most endangered marine
macroinvertebrate by the European Council Directive 92/43/EEC on the Conservation
ofNatural Habitat of Wild Fauna and Flora, 1992. It is distributed along rocky shores of
different lithologies that are exposed to medium to strong wave energy and are between
the high midlittoral and supralittoral zones (Biagi and Poli 1986; Laborel-Deguen and
Laborel1991 ; Ramos 1998). Patellaferruginea is a protandrous species (Espinosa et al.
2008) in which the male achieves sexual maturation at the age of2- 3 years (Laborel-
Deguen and Laborel 1991). Females produce relatively large-sized eggs, suggestive of
lecithotrophic development (Laborel-Deguen and Laborel1991). The species has
trochophora and veliger phases (Espinosa et al. 20 l O); however, few data are available
with regard to the biology and duration of its larva! phases.

The occurrence of shells in Palaeolithic and Neolithic deposits suggests that the
species was commonly distributed in the Western Mediterranean throughout the
Pleistocene to modem times (Espinosa and Ozawa 2006). Since prehistoric times,
intense human exploitation of P. ferruginea has led to the fragmen tation of the species'
range (Paracuellos et al. 2003). It is currently restricted to the following areas: Sardinia,
Corsica, Tuscan Archipelago, few scattered sites in Sicily, Pantelleria, and the North
African shoreline from Tunisia to the Strait of Gibraltar (Biagi and Poli 1986; Guerra-
Garcia et al. 2004).

The extent to which this fragmentation has affected the genetic population
structure of the species is not clear (Espinosa and Ozawa 2006; Casu et al. 2006). An
analysis of the mitochondrial DNA (mtDNA) region coding for Cytochrome c Oxidase
subunit I (COI) has shown a lack of genetic population structure in the populations

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Gìan Luca Dedola: ANALISI DELLA VARIABILITÀ GENETICA DI PATELLA FéRRUGINEA, PATEL-LA ULl'SSIPONENSIS (MOLLUSCA: GASTROPODA) E PINNA
NOBILIS (MOLLUSCA: BIVALVIA): lLCONTRJBUTO DEl DATI MOLECOLARl ALLA CONSERVAZIONE DI SPECIE MINACCIATE - Tesi di douorato in Scienze
della natura e delle sue risorse · indiri7.zo BK>logi.a Ambientale, Università degli Studi di Sassarl