''Amphicyclotulus amethystinus'' 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 tropical

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 ...

with a

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

and an operculum, 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 ...

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

Neocyclotidae Neocyclotidae is a family of tropical land snails with gills and an operculum, terrestrial gastropod mollusks in the informal group Architaenioglossa belonging to the clade Caenogastropoda (according to the taxonomy of the Gastropoda by Bouche ...

Shell description

The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard ou ...

is smooth, shining, not striate spirally, generally somewhat more depressed, deep chestnut or reddish brown.

Whorls 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 d ...

are a little flattened near the suture. The species may have subtle spiral striation, although there exists considerable variation; axial growth lines are clearly visible. The operculum is horny, diaphanous, concave externally, cartilaginous within, the nucleus projecting internally; with from ten to fourteen very narrow whorls, their rather lamellar outer edges slightly free. ''Amphicyclotulus amethystinus'' has spiral threads absent or only weakly present. There are found only two species in the genus ''Amphicyclotulus'' in Dominica. The other species is ''

Amphicyclotulus dominicensis ''Amphicyclotulus dominicensis'' is a species of tropical land snail with a gill and an operculum, a terrestrial gastropod mollusk in the family Neocyclotidae. Distribution This species is endemic to the West Indian island of Dominica.Robin ...

'' and it has spiral cords clearly present and raised.

Robert John Lechmere Guppy Robert John Lechmere Guppy (15 August 1836 in London – 5 August 1916 in San Fernando, Trinidad and Tobago) was a British-born naturalist after whom the guppy is named. He contributed much to the geology, palaeontology and zoology of the West In ...

(1868) noted that this species is not found above 1000 m. Although he recognized two “forms”, he did not recognize two separate species.

George French Angas George French Angas (25 April 1822 – 4 October 1886), also known as G.F.A., was an English explorer, naturalist, painter and poet who emigrated to Australia. His paintings are held in a number of important Australian public art collections. ...

(1884) subsequently recorded “''Cyclophorus amethystinus''” from altitudes above 1200 m.

Paul Bartsch Paul Bartsch (14 August 1871 Tuntschendorf, Silesia – 24 April 1960 McLean, Virginia) was an American malacologist and carcinologist. He was named the last of those belonging to the "Descriptive Age of Malacology". Early life Bartsch emigrate ...

(1942) Bartsch P. (1942). "The cyclophorid mollusks of the West Indies, exclusive of Cuba": 43-141. In: Torre C. de la, Bartsch P. & Morrison J. P. E. (1942). ''The cyclophorid operculate land mollusks of America". ''Bulletin United States National Museum'' 181: 1-306, pls 1-42. restricted the name ''amesthystinus'' to Guppy’s var. β, the “smooth, shining, not striate spirally” form.

Distribution

Amphicyclotulus amethystinus and Amphicyclotulus dominicensis map

This species is endemic to in

Dominica Dominica ( or ; Kalinago: ; french: Dominique; Dominican Creole French: ), officially the Commonwealth of Dominica, is an island country in the Caribbean. The capital, Roseau, is located on the western side of the island. It is geographically ...

. The type locality is

Laudat Laudat is a small village in the interior of Dominica, located between 3 mountains: Morne Watt, Morne Micotrine (Morne Mackak), and Morne Trois Pitons. With a population of just above 300 people, Laudat is referred to as a "gateway" because it is ...

, Dominica. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

is in

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

under number 535856. All known localities of ''Amphicyclotulus amethystinus'' include: *

Saint Andrew Parish, Dominica Saint Andrew is one of Dominica's 10 administrative parishes. It is bordered by St. John and St. Peter (to the west), St. Joseph (to the southwest), and St. David (to the southeast). At 178.27 km² (68.83 mi²),Figures provided by th ...

: west of

Calibishie Calibishie is a village in Dominica, located on the north-east coast of the island, immediately to the east of the village of Hampstead, Dominica, Hampstead. The Calibishie Coast Travel Area is thought by many to be the most scenic and unspoiled r ...

, Hampstead Estate * Saint Andrew Parish, Dominica:

Carib Territory The Kalinago Territory, previously known as the Carib Reserve or Carib Territory, is a district in the Caribbean island-nation of Dominica. It was established for the indigenous Kalinago people who inhabited the region prior to European coloniz ...

* Saint Andrew Parish, Dominica: Marigot, Captain Bruce * Saint Andrew Parish, Dominica: 1 km northwest of Thibaud *

Saint David Parish, Dominica Saint David is one of Dominica's ten administrative parishes, located on the eastern side of the island. It is bordered by St. Andrew to the north; St. Joseph, St. Paul and St. George to the west; and St. Patrick to the south. It has an area of 13 ...

Emerald Pool Emerald Pool is the name of several locations. Yosemite Emerald Pool is a small, shallow lake, with an area of less than one acre. It is located about 80 meters above Vernal Fall in Yosemite National Park. It is named for its deep green colo ...

* Saint David Parish, Dominica: 1.5 km north of Petit Savane * 0.5 km south of

Rosalie River bridge Rosalie may refer to: People * Rosalie (given name) * Rosalie Levasseur (1749-1826), French soprano billed as Mademoiselle Rosalie * Rosalie Rendu or Sr. Rosalie (1786–1856), venerated by the Roman Catholic Church Film and theater * ''Rosalie' ...

Saint George Parish, Dominica Saint George is one of Dominica's 10 administrative parishes. It is bordered by Saint Paul and part of the Boeri River (to the north), Saint David and Saint Patrick (to the east), Saint Luke (to the south). The parish has an area of 56.1 km ...

Bellevue Chopin Bellevue means "beautiful view" in French. It may refer to: Placenames Australia * Bellevue, Western Australia * Bellevue Hill, New South Wales * Bellevue, Queensland * Bellevue, Glebe, an historic house in Sydney, New South Wales Canad ...

* Saint George Parish, Dominica: Freshwater Lake area * Saint George Parish, Dominica: trail to Lake Boeri *

Saint Joseph Parish, Dominica Saint Joseph is one of Dominica's 10 administrative parishes. It is bordered by St. Peter to the north, St. Andrew to the northeast, St. David to the east, and St. Paul to the south. It has an area of 120.1 km² (46.37 mi²), and a p ...

: d’Leau Grommier * Saint Joseph Parish, Dominica: road to Fond Cassé, Mary Martin Farm * Saint Joseph Parish, Dominica: path Mero-

Salisbury Salisbury ( ) is a cathedral city in Wiltshire, England with a population of 41,820, at the confluence of the rivers Avon, Nadder and Bourne. The city is approximately from Southampton and from Bath. Salisbury is in the southeast of Wil ...

Saint Luke Parish, Dominica Saint Luke is one of Dominica's 10 administrative parishes. It is bordered by St. George (to the north), St. Mark (to the south), and St. Patrick (to the east). The parish is one of Dominica's smallest in area and population. 1,668 peopleCommonw ...

Pointe Michel Pointe Michel is a small town on the southwest coast of Dominica. It is located to the south of the capital, Roseau, and is known for being the birthplace of Dominica's first (and to date only) female Prime Minister A prime minister, premi ...

Saint Paul Parish, Dominica Saint Paul is one of Dominica's 10 administrative parishes. It is bordered by St. Joseph to the north, St. David to the east, and St. George to the south. It has an area of 67.4 km² (26.02 mi²), and a population of 8,397.

: Sylvania *

Saint Peter Parish, Dominica Saint Peter is one of Dominica's 10 administrative parishes. It is bordered by St. John to the north, St. Joseph to the south, and St. Andrew to the east. It has an area of 27.7 km² (10.74 mi²), and has a population of 1,452, the l ...

: Syndicate.

References

This article incorporates CC-BY-3.0 text from the reference and public domain text from the reference. , name = ''Amphicyclotulus amethystinus'' {{Taxonbar, from=Q4748239 Neocyclotidae Endemic fauna of Dominica Gastropods described in 1868