Terrestrial Molluscs

The Madeira Archipelago belongs to the group of oceanic islands with the greatest diversity of terrestrial molluscs per area unit, having 291 species spread out over 31 families and 84 kinds, 19 of which are specific of the archipelago.

The Ponta de São Lourenço contains one of the most important terrestrial mollusc fossil deposits in Europe from the Quaternary Period. The peculiarity presented by some of the these species, resulting from evolution and adaptation processes occured in situ, made this area a place of reference.

The Porto Santo Island presents the greatest diversity of terrestrial molluscs species per area unit in the world. Its fauna is extremely rich, and some of its islets even include exclusive species.

In the Desertas islands, there are terrestrial molluscs subspecies of high importance, which have reulted from the former conection to the Madeira Island, where the contact and isolation of these islands might have allowed the divergence of species.

The Selvagens islands have an endemic species exclusive of this area, Theba macandrewiana,although this is not frequently mentioned.

Due to the above mentioned, the relevance of the malacological fauna of the Madeira Archipelago becomes clear, both worldwide and regionally. However, the latter is classified by the IUCN as vulnerable, among which 64 species have the threatening statute. The reason why this number is not higher is because most of the terrestrial molluscs species of the archipelago are not evaluated. Human action has had catastrophic consequences on the malacological fauna, where 9 out of the 14 registered extinctions occured after human colonization.

Marine Molluscs

The marine molluscs belong to the Phylum Mollusca, which is the phylum with the greatest diversity of species following the Phylum Arthropoda (about 50.000 live species and 35.000 fossil species).

The molluscs, mostly aquatic, have a soft and non-segmented body, often divided into a head with sensory organs, a muscular foot and a mantle that protects a part of the body and frequently separates a shell.

There are herbivorous and carnivorous molluscs, filter feeders and molluscs of all known feeding strategies. They are extremely diverse in terms of dimension and morphological differentiation and may of them are known for their decorative shells.

Several molluscs are consumed in the human diet like the Octopus, the Squid, the Limpet and other bivalves.