''Amastra antiqua'' 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 antiqua antiqua'' (Baldwin, 1895) * ''Amastra antiqua kawaihapaiensis'' Pilsbry & C. M. Cooke, 1914

Description

The length of the shell attains 20 mm, its diameter 12 mm. (Original description) The shell contains 6

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. The fossil shell is dextral, narrowly yet deeply perforated, with the perforation extending nearly to the

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 ...

. It is solid and elongately ovate, with a subacute apex. The surface is sculptured with coarse, irregular growth lines, while the apical whorls are smooth. The color of the living shell is unknown. The shell consists of six convex whorls, separated by a well-impressed suture. 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 slightly oblique and sublunate. The peristome is thickened on the inner side, with the columellar margin adnate and slightly expanded over the umbilicus. The extremities of the peristome converge and are united by a thick parietal callosity. 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 flexuous, ending in a narrow plait. The sculpture consists of coarse, uneven wrinkles separated by finely and irregularly striated intervals. The embryonic shell appears smooth in the fossil specimens. The shell is narrowly umbilicate rather than "perforated", as previously described by Mr. Baldwin, with the umbilicus measuring nearly 1 mm in width. The spire is slightly contracted near the summit. The peristome is obtuse and features a callous rib on the inner side. A low, oblique nodule or callous ridge is present on the parietal wall, situated some distance within and above, relatively close to the origin of the columella. In adult shells, the parietal callus is notably thickened at the edge.

Distribution

This species is

endemic Endemism is the state of a species being found only 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 foun ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, 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 ...

Island.

References

External links

* {{Taxonbar, from=Q131402561 antiqua Gastropods described in 1895