''Caseolus abjectus'' is a

species In biology, a species is the basic unit of 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 the appropriate s ...

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...

in the family

Geomitridae Geomitridae is a Taxonomy (biology), taxonomic Family (biology), family of small to medium-sized air-breathing land snails, Terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea.MolluscaBase eds. (2021). M ...

, the hairy snails and their allies. It 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 elsew ...

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 ...

, where it occurs on three islands in the archipelago. The subspecies ''C. abjectus abjectus'' occurs on

Porto Santo Island Porto Santo Island () is a Portuguese island northeast of Madeira Island in the North Atlantic Ocean; it is the northernmost and easternmost island of the archipelago of Madeira, located in the Atlantic Ocean west of Europe and Africa. The muni ...

. It has a limited range but it is an abundant snail where it does occur. The subspecies ''C. abjectus nesiotes'' occurs mostly on

Bugio Bugio Island ( pt, Ilha do Bugio) — is one of the three islands of the Portuguese Desertas Islands archipelago, a small chain of islands in the Madeira Islands Archipelago of Macaronesia. It is located in the Atlantic Ocean off the western coa ...

and has been found at one site on Deserta Grande. There its habitat has been degraded by the overgrazing of introduced goats. The goat population has been reduced as a conservation measure for the habitat on the islands, improving the outlook for the snail subspecies.

References

abjectus Molluscs of Madeira Endemic fauna of Madeira Porto Santo Island Gastropods described in 1831 Taxonomy articles created by Polbot {{Geomitridae-stub