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night hours restricting their movement to about eight hours per day (Peharda and
Vilibié, 2008). Furthermore, the larvallife cycle of this species, as it happens in alrnost
all species of class Bivalvia, could be strongly affected by environmental conditions of
its habitat such as temperature, salinity and food ratio (Gosling, 2003). For this reason,
potential for dispersa! and gene flow characterizing Mediterranean populations of P.
nobilis should be evaluated in the light of their geographic distribution and
environmental conditions across the basin.

Even if the species is distributed throughout the whole Mediterranean, till now
only populations belonging to few areas bave been investigated. In particular the
literature provides works dealing with ecologica! aspects of populations from the Gulf
ofLion (Vicente, 1990), the Ionian Sea (Giacobbe and Leonardi, 1987; Centoducati et
al., 2007), the Balearic Sea (Garcia-March, 2005), the Adriatic Sea (Peharda and
Vilibié, 2008), the Sardinian (Porcheddu et al. 1998; Caronni et al. 2007; Addis et al.
2009) and Tunisian coastline (Tlig-Zouari, 1993; Rabaoui et al., 2008, 2010) and the
Aegean Sea (Katsanevakis, 2005; Galinou-Mitsoudi et al., 2006).

The only two studies carried out on the molecular aspects of this species,
analyzed Mediterranean populations from Aegean Sea (Katsares et al., 2008) and
Tunisian coasts (Rabaoui et al., 2011).
The former study analysed the genetic variability of four Greek populations obtained by
means ofthe mitochondrial markers Cytochrome c Oxidase subunit I (COI) and 16S
rDNA. High levels of haplotypic diversity were found for COI gene even considering
the lack of genetic structuring among populations. On the other band, Rabaoui et
al.(2011) used COI sequences to describe the genetic variability of five populations
from northern, eastern, and southern Tunisian coastline and further evaluated wether the
two morphological forms ofthis species were genetically differentiated.The authors

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Gìan Luca Dedola: ANALISI DELLA VARIABILITÀ GENETICA DI PATELLA FéRRUGINEA, PATEL.LA UL l'SSIPONENSIS (MOLLUSCA: GASTROPODA) E PINNA
NOBILIS (MOLLUSCA: BIVALVIA): lLCONTRJBUTO DEl DATI MOLECOLARI 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