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presence of a typical “insular” fauna; Tellina balaustina and Lepidopleurus (P)
africanus were the unique two species found in all archipelagos and Ustica island. Only
Partenopean and Pontine archipelagos were relatively associated, with 17 species in
common.

Fig. 2 - Bray-Curtis similarity index applied to presence/absence data transformed of the island molluscs
of all archipelagos considered.

CONCLUSIONS
On the whole, the present data lead to the collection of an historical data-set of the

malacofauna of the South-Tyrrenian archipelagos, potentially useful for future studies
concerning the AMPs’ effectiveness in the protection of biodiversity.

The malacocoenoses studied didn’t allow to highlight a common typical insular
fauna, even if the majority of soft-bottom found in the framework of this study was
characterised by analogous environmental situations (coarse sediments down to 100 m).

At least two “anomalous” stations, in the Vulcano and Palmarola islands, with
high densities of species indicators of organic enrichment, were found. The absence of
major inhabited centres in the area make us prone to consider them as “decantation
zones” with a natural accumulation of organic matter.

Only two species of molluscs, the bivalve Tellina balaustina, and the polyplaco-
phoran Lepidopleurus (Parachiton) africanus Nierstrasz, 1906, turned out to be the
single species present in all the four archipelagos and the Ustica Island. Curiously, L.
(P.) africanus is cited among the rarest Mediterranean chiton species. Its known
habitats, the coastal detritic biocoenoses (DC) and in particular in the maerl facies, are
confirmed.

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