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| Amastra irwiniana | |
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| Shell of Amastra irwiniana (holotype) | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Stylommatophora |
| Family: | Amastridae |
| Genus: | Amastra |
| Species: | A. irwiniana |
| Binomial name | |
| Amastra irwiniana C. M. Cooke, 1908 | |
| Synonyms | |
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Amastra (Metamastra) irwiniana E. A. C. M. Cooke, 1908 alternative representation | |
Amastra irwiniana is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae.
Description
The length of the shell attains 11.2 mm, its diameter 7.2 mm
The shell is minutely but distinctly perforate, dextral, and globosely conical with slightly concave outlines. It is thin, with distinctly irregular and closely spaced growth striae, and lacks gloss. The upper whorls and the base of the body whorl are light brown with a faint yellowish tinge, while the upper portion of the body whorl is dark chestnut.
The spire is slightly concavely conical with an acute apex. The suture is simple and well impressed. There are 6½ whorls, with the embryonic ones slightly swollen, the fourth and fifth slightly flatter, and the body whorl being convex and tumid, featuring an almost obsolete angle at the periphery and tapering toward the base.
The aperture is relatively large, bluish on the interior, and shaped like a slightly oblique sector of a circle. The columella is straight, bearing a nearly median, rather large, thin, and slightly oblique fold. The outer lip is thin, slightly thickened within, erect, and regularly curved, forming a distinct angle with the base of the columella. The columellar margin is thin and reflexed above the umbilicus. The umbilicus itself is minute and semicircular.
Distribution
This species is endemic to Hawaii, occurring on Oahu island.
References
- Amastra irwiniana C. M. Cooke, 1908. 12 December 2024. Retrieved through: World Register of Marine Species.
- Hyatt, A. & Pilsbry, H. A. (1910–1911). Manual of conchology, structural and systematic, with illustrations of the species. Ser. 2, Pulmonata. Vol. 21: Achatinellidae (Amastrinae). Philadelphia: Conchological Department, Academy of Natural Sciences. p. 240. Retrieved 3 December 2024.
{{cite book}}: CS1 maint: multiple names: authors list (link)
This article incorporates text from this source, which is in the public domain.
- Cowie, R. H., Evenhuis, N. L. & Christensen, C. C. (1995). Catalog of the native land and freshwater molluscs of the Hawaiian Islands. Leiden: Backhuys Publishers. p. 106.
{{cite book}}: CS1 maint: multiple names: authors list (link)
External links
- Cooke, CM Jr. (1908). "hree new species of Amastra from Oahu". Occasional Papers of the Bernice P. Bishop Museum of Polynesian Ethnology and Natural History. 3 (2): 215–216. Retrieved 12 December 2024.