''Testudodiscula testudinalis'' a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of small land snail, a

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

pulmonate gastropod mollusc in the family

Geomitridae Geomitridae is a taxonomic family of small to medium-sized air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea.MolluscaBase eds. (2021). MolluscaBase. Geomitridae C.R. Boettger, 1909. Accessed throu ...

Distribution

This species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to the island of

Madeira ) , anthem = ( en, "Anthem of the Autonomous Region of Madeira") , song_type = Regional anthem , image_map=EU-Portugal_with_Madeira_circled.svg , map_alt=Location of Madeira , map_caption=Location of Madeira , subdivision_type=Sovereign st ...

, Portugal.

Shell description

The shell of these snails is shaped like a discus, or a

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'' ...

, with a sharp edge around the periphery of the whorls.

Conservation status

This species is critically endangered, as mentioned in annex IV of

Habitats Directive The Habitats Directive (more formally known as Council Directive 92/43/EEC on the Conservation of natural habitats and of wild fauna and flora) is a directive adopted by the European Community in 1992 as a response to the Berne Convention. The ...

References

Discula Gastropods described in 1852 {{Geomitridae-stub