This is an old revision of this page, as edited by JoJan (talk | contribs) at 20:09, 25 December 2024 (link). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 20:09, 25 December 2024 by JoJan (talk | contribs) (link)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) Species of gastropod
| Amastra violacea | |
|---|---|
| |
| Amastra violacea shell | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Stylommatophora |
| Family: | Amastridae |
| Genus: | Amastra |
| Species: | A. violacea |
| Binomial name | |
| Amastra violacea Newcomb, 1853 | |
| Synonyms | |
| |
Amastra violacea is a species of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Amastridae.
- Subspecies
- Amastra violacea violacea (Newcomb, 1853)
- Amastra violacea wailauensis Hyatt & Pilsbry, 1911
Description
The length of the shell attains 27.9 mm, its diameter 14 mm.
The shell is dextral, ovate-oblong, and solid, consisting of 7 convex whorls that are prominently striated longitudinally. The suture is plain yet deeply impressed, adding to the shell's defined appearance.
The aperture is ovate, with a short columella that ends in a distinct twisted plait. The outer lip is simple, while the shell's coloration is violaceous, adorned with lighter-colored striae for contrast.
Thetypical form is well characterized by its violaceous hue with light striae, a purplish apex, and yellowish earliest neanic whorls, with a purple interior. In some cases, the shell surface appears more worn and adopts a nearly uniform flesh tone, with the apex becoming nearly white. Fragments of the thin brown cuticle may persist, and when preserved on the spire, reveal irregular dark markings on a lighter background, indicating a relationship to A. nubilosa.
The whorls of the protoconch form a rather acute, conic summit, with the first half whorl smooth. Weak, low axial ribs develop shortly afterward. The second whorl features rather strong, arcuate ribs, which are broader than their intervals and often split or weaken near the lower suture. On the next whorl, the ribs become finer and weaker below the middle, sometimes splitting into striae. Approximately 3.5 embryonic whorls are present, with their outlines being nearly flat.
The subsequent whorls are moderately convex, with somewhat thread-like striae. These may be low or partially effaced in areas. The columellar fold is relatively small and oblique. The outer lip is thin, contributing to the shell's delicate appearance.
Distribution
This species is endemic to Hawai, occurring off Halawa.
References
- "WoRMS - World Register of Marine Species - Amastra elongata (Newcomb, 1853)". www.marinespecies.org. Retrieved 2024-11-19.
- Amastra violacea (Newcomb, 1853). 25 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. 257. Retrieved 2 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. vi. Leiden: Backhuys Publishers. p. 107.
{{cite book}}: CS1 maint: multiple names: authors list (link)
External links
- Newcomb, W. (1853). "Descriptions of new species of Achatinella from Sandwich Islands". Annals of the Lyceum of Natural History of New York. 6: 26.
- Conchology.be: image