''Amastra turritella'' 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 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 molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...

, 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 ...

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 inclu ...

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 ...

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

in the family

Amastridae Amastridae is a Taxonomy (biology), taxonomic family (biology), family of small, air-breathing, land snails, Terrestrial animal, terrestrial pulmonate gastropod mollusks in the superfamily Pupilloidea.MolluscaBase eds. (2021). MolluscaBase. Amast ...

. ;Subspecies: * ''Amastra turritella aiea'' Hyatt & Pilsbry, 1911 * ''Amastra turritella turritella'' (A. Férussac, 1821) * ''Amastra turritella waiawa'' Hyatt & Pilsbry, 1911

Description

The length of the shell can reach 20 mm, its diameter 8.7 mm The shell is dextral, elongate, and conic with fine striations. It consists of six

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). In nature File:Photograph and axial plane floral diagra ...

s, ending in an obtuse

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

. The suture is distinct and simple, not duplicated. The

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is prominently oblong, with the

peristome Peristome (from the Greek language, Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mo ...

thickened on the interior margin. The

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

is nearly straight, perforate, and features a well-defined rib, adding to its structural detail. The typical form, as illustrated by Ferussac, is characterized by a chestnut-brown coloration. The embryonic shell often appears darker with a purplish hue, although it can also present as whitish-corneous or flesh-colored. The apex is relatively blunt and rounded, with the second embryonic whorl displaying very fine vertical striae, occasionally interrupted by weak spiral lines. In the adult stage, the shell surface is marked with fine striae overlaying low growth wrinkles. The subsutural region is usually a paler shade, providing a subtle contrast. The aperture is blue-white internally, sometimes exhibiting a faint pink tint. The outer lip is sharp, while the columellar plica is moderately strong, occasionally accompanied by a subtle, oblique fold positioned above it. The axis is generally perforate, completing the distinctive features of the shell. The animal is compact, measuring only half the length of the shell. It is predominantly dark slate-colored along the sides, with the superior portion and tentacles a deep black. The underside of the foot is light gray, while the mantle is a rich dark brown, adding a subtle contrast to its overall appearance.

Distribution

This species is endemic to Hawai, occurring on

Oahu Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...

References

External links

* * * {{Taxonbar, from=Q131584384

turritella ''Turritella'' is a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Turritellidae.Vos, C.; Gofas, S. (2013). Turritella Lamarck, 1799. Accessed through: World Register of Marine Species at http://www. ...

Gastropods described in 1821