Page 3 - Scuderi_Balistreri_Germanà_2019

Are Pinctada radiata and P. fucata only synonyms or really different species? The case of some Mediterranean populations 417

Nowadays throughout the Southern Central and on the morphology of both the shell and the soft
Eastern Mediterranean P. radiata can be considered body parts.
a well-established species. Comments and personal interpretations of the
But the genetic diversity of populations of this taxonomical status of both these morphs are here
species in the basin seems to exhibit low values, as reported as an attempt to give our contribution to
reported by Barbieri et al. (2015). their complicated taxonomy.
In this last years in Sicily consistent materials
of another morphologically different population of
Pinctada were found along the Eastern coast (Vil- MATERIAL AND METHODS
lari & Scuderi, 2017), from Messina to Siracusa,
in different environmental conditions compared to A total number of 1284 living specimens and
the quantitatively less important finding of P. ra- shells of both the morphs were examined from
diata. many different Mediterranean localities, from cen-
As suggested by these latter Authors, the model tral N-African coasts to the more Eastern places of
of settlement and spreading of this populations in the basin (Fig. 1), and grouped according to the col-
these localities follows the model of a newly en- lection site in the Mediterranean, studying the vari-
tered alien species. In fact specimens appeared in ation inside populations.
massive quantities in these localities where no other More accurate data are furnished in Table 2 for
specimen of Pinctada since XIX century was pre- each morph debated in the following lines.
viously recorded, with the exception of only one The most abundant population is that from the
single shell in the harbor of Catania (Di Geronimo, sandy coast of Catania (E-Sicily), where numerous
1971). alien species of animals and algae are constantly
The Northern and the most Southern part of the found during these last years.
island was reached only in a second time, with less Living specimens were found on a removable
consistent populations, being the harbor of Catania containment boom, which was installed on June 15
identified as the location of first settlement, proba- 2018 and removed on September 18 of the same
bly after human mediated transportation. year. Some Indo-Pacific specimens of P. fucata,
Currently the population of Eastern Sicily ben- from Maldives Islands, were studied for morpho-
efits a good state of health, since large number of logical comparisons.
specimens were found just in winter 2018. Specimens were measured and the shell mor-
In the present paper, the taxonomic conundrum phology was studied: nomenclature of characters
previously reported was re-examined applying mor- follows Wada & Temkin (2008).
phological taxonomy to the above mentioned ma- We utilized as valid characters: the general out-
terials of both the morphs of Pinctada. line, the sculpture and the prevalent colour of
The study of this materials allowed us to dis- valves, the hinge structure and the shape of liga-
criminate two different groups on account of shell ment and ligament area.
morphology, anatomy of the external soft parts and Living specimens were housed in aquarium and
environment. dissected: specimens of the two morphs were com-
The first could be grouped under the so far parable in size (Figs. 39, 41).
known taxon P. radiata, while, according to us, the Anatomical studies concerned the presence and
second represents a different species which here we shape of the anal funnel and colour of soft parts.
call P. fucata, after comparisons with Indo-Pacific Table 1 lists the main characters utilized to dis-
material. So, the real question is more general and tinguish P. radiata and P. fucata used in this study.
trespass the Mediterranean limits: are these two ACRONYMS AND ABBREVIATIONS. AGC:
taxa only synonyms of a single very variable Alfio Germanà Collection, Catania, Italy; AVC: Al-
species or they could indeed be considered a differ- berto Villari Collection, Messina, Italy; DSC:
ent species? A resume of the literature data on bio- Danilo Scuderi Collection, Catania, Italy; PBC:
molecular studies conducted to solve doubts on the Paolo Balistreri Collection, Favignana, Trapani,
identity of species of this complex are here fur- Italy; PMC: Pasquale Micali Collection, Fano,
nished together with our new personal observations Italy; WRC: Walter Renda Collection, Amantea,