Testudinalia testudinalis is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sea snail

Sea snail

Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

, a true limpet, a marine gastropod mollusk in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Lottiidae

Lottiidae

Lottiidae is a family of sea snails, specifically true limpets, marine gastropod mollusks in the superfamily Lottioidea and the clade Patellogastropoda .- 2005 taxonomy :...

, one of the families of true limpets. It is commonly known as the plant limpet or tortoiseshell limpet.

Description

T. testudinalis has a low domed shell, oval in outline. It can grow to up to 30 x 24 x 10 mm but typically is about half this size. The apex is towards the anterior of the shell and fine ridges radiate from it. The shell is banded with brown and white. The mantle is the part of the body wall immediately under the shell and at the edges it is curled round to form a collar. The foot is broad and oval. The head bears two sensory tentacles with a tiny black eye at the base of each.

Distribution and habitat

T. testudinalis occurs in northern regions of both the Pacific and Atlantic Oceans. It is found in the neritic zone

Neritic zone

The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters...

 from low water mark down to a depth of about fifty metres. It is usually found on stones and boulders, especially those encrusted with red crustose algae such as Lithothamnion

Lithothamnion

Lithothamnion is a genus of thalloid red alga comprising 103 species. Its members are known by a number of common names.Recorded common names are griuán, maërl, punalevä-suku, stenhinna and maerl. The monomerous, crustose thalli are composed of a single system of filaments which grow close to the...

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