Sunday, July 3, 2011

The pomatias

Pomatias sulcatus
I recently took some pictures of an interesting species of snail but although I found its scientific name I could not find a common name for it so as its scientific name is Pomatias sulcatus, I used part of this name for the title of this article.

This species of land snail is found throughout the western Mediterranean. It is common on calcareous soils near the coast and inland. It can be found on soil, in crevices in rocky ground, under stones and among fallen leaves. Sometimes it buries itself in the soil while the specimens I photographed were living on a tree trunk. In the Maltese island it is common on Malta, Gozo and Comino as well as on some of the smaller islands.
There was and probably still is some controversy about this snail in the Maltese islands. Some biologists have listed it as a distinct species endemic to the Maltese island others as a subspecies while others believe that the snails found on Malta are not different enough from the snails found in other parts of the Mediterranean to be considered as a separate species or subspecies.

Pomatias sulcatus is not the only species of pomatias that can be found in the Maltese islands. Another species, Pomatias elegans which is known as the round mouthed snail, can be found at San Anton Gardens at Attard. It probably found its way there on imported plants. This species is common in southern Europe and lives in similar habitats as Pomatias sulcatus.

The pomatias are one of the few groups of land snails that have an operculum. This is a calcareous structure like a small lid that fits neatly in the opening of the shell sealing the soft body inside. The operculum is found in most species of marine and freshwater snails but very rarely in land snails. Its main function is to prevent desiccation especially in those species that live in the intertidal or splash zone of the coast. The presence of an operculum in the pomatias suggests that these snails evolved from marine snails. 

This article was published in The Times on 06.04.10

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