''Assiminea grayana'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

the "dun sentinel", is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of very small (4–6 mm.)

salt marsh A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. 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 o ...

(or marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Assimineidae Assimineidae is a family (biology), family of small snails, also known as palmleaf snails, with an Operculum (gastropod), operculum, gastropod mollusks or micromollusks in the superfamily Truncatelloidea. Many of these very small snails live in i ...

Habitat

This species lives in habitats that are intermediate between land and saltwater: in estuaries and

es, at, or right above, the high tide level.

Description

The 5 mm high x 3 mm. wide shell is semi-transparent and conical, with six or seven flat-sided or slightly swollen whorls and a sharp apex. It bears fine irregular growth lines and faint spiral lines but appears smooth . The oval or ear-shaped aperture is small and has a thickened peristome. The inner lip is reflexed over the base of the last whorl. There is no umbilicus. The colour is horn or tan, often with a broad reddish band on the last whorl.

Distribution

This small snail lives in

Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

, primarily on the southern part of the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

coasts, in countries and islands including: *

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

The Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

Reproduction

This species reproduces sexually. The male has a penis in the middle, or at least close to the middle, of his head. The female has a series of translucent glands the lead to a seminal receptacle, where an egg waits for the semen.Hallan, Anders, et al. “Two New Species of OvassimineaThiele, 1927 (Truncatelloidea: Assimineidae) from Tropical Australia.” Molluscan Research, vol. 35, no. 4, 2015, pp. 262–274., doi:10.1080/13235818.2015.1053171.

References

External links

''Assiminea grayana''
at

Animalbase AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and p ...

''Assiminea grayana''
Species account and photograph at Mollusc Ireland. Assimineidae Gastropods described in 1828 {{Assimineidae-stub