| Amastra nigra | |
|---|---|
| |
| Shell of Amastra nigra | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Stylommatophora |
| Family: | Amastridae |
| Genus: | Amastra |
| Species: | A. nigra |
| Binomial name | |
| Amastra nigra (Newcomb, 1855) | |
| Synonyms | |
| |
Amastra nigra is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae.
- Subspecies
- Amastra humilis moomomiensis Pilsbry & C. M. Cooke, 1914
- Amastra humilis sepulta Pilsbry & C. M. Cooke, 1914
Description
The length of the shell attains 17 mm, its diameter 11.2 mm
The dextral shell is globosely acuminate, moderately solid, and composed of 6 whorls. The two lower whorls are prominently inflated, contrasting with the subulate superior whorls. The last two whorls display a rugged surface, characterized by coarse longitudinal striae intersected by irregularly spaced, revolving ridges that form rough cicatrices. The upper whorls are flattened and densely marked with pronounced longitudinal striae. The suture is simple, distinct, and well-impressed.
The aperture is roundly ovate, with a short columella ending in a well-defined lamellar tooth. The shell is a yellowish-white hue, coated with a delicate black epidermis.
The second embryonic whorl is nearly flat-sided, featuring a sculpture of strong, curved riblets and a prominent carina above the suture. The following whorl displays fine ribbing, which is partially effaced at its center. The final, highly globose whorl is distinctly malleated, characterized by flattened facets and irregular, descending spiral ridges.
The spire is brown, while the body whorl, beneath its dull, blackish cuticle, is almost white. The cuticle is irregularly adorned with angular streaks on the spire. The outer lip is reinforced by a prominent rib or a delicate callus on the inner surface.
Distribution
This species is endemic to Hawaii, occurring on Maui island.
References
- Amastra nigra (Newcomb, 1855)21 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. 293. Retrieved 3 December 2024.
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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
- Newcomb, W. (1855). "Five species of Achatinella". Proceedings of the Boston Society of Natural History. 5: 219. Retrieved 21 December 2024.
- Pfeiffer, L. (1856). "Descriptions of twenty-three new species of Achatinella, collected by Mr. D. Frick in the Sandwich Islands; from Mr. Cuming's colle". Proceedings of the Zoological Society of London. 23 (297): 207. Retrieved 21 December 2024.