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416 DANILO SCUDERI ET ALII

still unknown species or the earliest reported lessep- As a consequence, a molecular phylogenetic ap-
sian species, as it was. Subsequently the species proach was used by some researchers but the results
was doubtfully described as new as Meleagrina were still discordant: see for instances Temkin
savignyi Monterosato, 1884 (Bivalvia Pteriidae), (2010) and Cunha et al. (2011).
later identified as Pinctada radiata (Leach, 1814) For this reasons, the former Author stated the lack-
(Parenzan, 1961; Bombace, 1967; Paccagnella, ing to date of precise constant morphological charac-
1967; Spada, 1969). ters, in particular to discriminate species of the so
Since modern times, this latter name has never called “P. radiata” group, for which three different
been questioned and nobody has ever doubted if clines have been distinguished and taxonomically re-
under this name more than one species could be lated by him to geographical sub-species: P. imbricata
hidden. imbricata Röding, 1798 in the western Atlantic areas,
Taxonomy of the species of Pinctada Röding, P. imbricata radiata in the eastern Indian Ocean and
1798 is complicated because of the extreme vari- the Red Sea areas and P. imbricata fucata in the Indo-
ability of species in this genus and seems far to be Pacific areas.
clearly defined. In fact P. radiata has been consid- As the modes of introduction of this pearl oyster
ered as conspecific with P. fucata (Gould, 1850) (see in the Mediterranean Sea, more than one have been
Hynd, 1955) and, later on, as mere synonyms (Ran- described in the literature: intentional introduction
son, 1961) (“alternate representation” in WoRMS). by mariculture; shipping, which is considered to
Some important factors, like wide geographical be the most likely introduction vector of non-in-
distribution and anthropic contribution to hybridiza- digenous species (Zibrowius, 1992) and even by
tion, are reported by Temkin (2010) as affecting the migrant trips of the sea turtle Caretta caretta (Lin-
extreme polymorphism of species. naeus, 1758) (Oliverio et al., 1992).

Figure 1. Map of the sampled area: red circles refer to P. radiata findings, yellow circles to
P. fucata findings. The “?” refers to doubtful provenance.