''Wollastonaria turricula'' 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 ...

of small, air-breathing

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 ...

, a terrestrial

pulmonate Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includ ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

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 ...

. MolluscaBase eds. (2022). MolluscaBase. Wollastonaria turricula (R. T. Lowe, 1831). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1340237 on 2022-07-21 This species is indigenous to the

Madeira archipelago ) , 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 only occurs on the islet

Ilhéu de Cima Ilhéu de Cima is an uninhabited island of Cape Verde. It is part of the Ilhéus do Rombo islet group, located east of Ilhéu Grande, the other main islet of the group, and northeast of the island Brava. They are administratively a part of the ...

Shell description

The shell of these snails is shaped like a discus, or a lens, with a sharp edge around the periphery of the

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

s. It may be easily distinguished, through external morphology, from all ''Hystricella'' and ''Wollastonia'' species from its "peculiarly turreted shell".

Distribution and Ecology

''Hystricella turricula'' is endemic to the coastal slopes and plateaus on the islet Ilhéu de Cima on the southeastern coast of Porto Santo. The species occurs under volcanic rocks and debris scattered in open fields. The local form ''pererosa'' occurs on steep low-elevation slopes. Referenced collecting localities of De Mattia, Neiber & Groh, 2015 include: Quaternary slope deposits on the southwestern coast of Ilhéu de Cima, 33°03'15"N 16°17'02"W, 40 m; Ilhéu de Cima, top, under stones, 33°03'13"N 16°16'48"W, approx. 100 m.

Conservation status

This species is mentioned in annex IV of the Habitats Directive. De Mattia, Neiber & Groh, 2015 consider this species to be Critically Endangered under criteria B1a,b(ii,v),2a,b(ii,v), as the species' extent of occurrence is less than 1 km², and is imperiled by grazing and various unrecorded factors. Significant populational declines have been recorded, and the species is now restricted to one location on a high-altitude plateau.

References

External links

Lowe, R. T. (1831). Primitiae faunae et florae Maderae et Portus Sancti; sive species quaedam novae vel hactenus minus rite cognitae animalium et plantarum in his insulis degentium breviter descriptae. Transactions of the Cambridge Philosophical Society. 4 (1): 1-70, pl. 1-6. Cambridge

De Mattia, W., Neiber, M. & Groh, K. (2018). Corrigenda: De Mattia W, Neiber MT, Groh K (2018) Revision of the genus-group Hystricella R. T. Lowe, 1855 from Porto Santo (Madeira Archipelago), with descriptions of new recent and fossil taxa (Gastropoda, Helicoidea, Geomitridae). ZooKeys 732: 1–125. https://doi.org/10.3897/zookeys.732.21677. ZooKeys. 733: 147-148
Geomitridae Taxa named by Richard Thomas Lowe Gastropods described in 1831 {{Geomitridae-stub