Common tortoiseshell limpet

The common tortoiseshell limpet, (Tectura testudinalis) also known as the plant limpet, lives by the sea on rocky shorelines. At high tide this mollusk is under water, whereas at low tide it emerges.

Limpet species are many. They’re easy to recognize because their shell is shaped like a “Chinese hat,” a sort of small flattened cone you find fastened to a rock and that is very difficult to dislodge. The limpet adheres so well to the rock that it forms an airtight contact zone that protects it from drying out at low tide. If we try to remove it, we risk breaking the shell instead, and killing the animal.

Limpets are gastropods, like snails. But while the latter have a coiled shell, with only the foot and head poking through the shell’s opening, limpets have a shell that forms a broad flared cone and that attaches solidly to rocks thanks to a single foot situated under the animal.

Some species present a heightened cone, while others are more flattened. There are even limpets whose cone is off-center. The shell presents brownish ridges and spots radiating from the top to the base. We also see concentric lines that make it possible to assess its growth (growth rings).

Seen from below, the shell is a bluish-white color. Also observable are its immense circular beige-brown foot as well as its small round head fitted with two tentacles (antennae) and a mouth. The foot hides the gills, which are located in the vicinity of the head, under the shell.

At the Biodôme, we’ve chosen Tectura testudinalis as a type species, since it’s very plentiful in the Gulf of St. Lawrence.