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Amastra decorticata

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Amastra decorticata
Shell of Amastra decorticata
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Stylommatophora
Family: Amastridae
Genus: Amastra
Species:
A. decorticata
Binomial name
Amastra decorticata
Gulick, 1873
Synonyms
  • Achatinella decorticata Baldwin, 1893
  • Amastra (Amastrella) decorticata E. A. C. M. Cooke, 1908 alternative representation
  • Laminella decorticata GuLick, W. G. Binney, 1884

Amastra decorticata is a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Amastridae.[1]

Description

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The length of the shell attains 16 mm, its diameter 8.5 mm

The shell is ovate-conic, dextral, and lightly striated with growth lines. Its coloration is chestnut, becoming blackish near the lip. There are 6 to 6½ whorls, which are slightly convex, with the first three being polished. The suture is simple and pale.

The aperture is weakly colored, with a dirty-blue interior. The peristome is thin, blackish on the inside, and only slightly thickened. The columellar fold is thin and delicate.

The shell lacks the conspicuously patched appearance typical of Amastra inflata and Amastra elliptica. However, under magnification, some small, dull streaks may be observed on its otherwise glossy surface, which generally lacks an epidermis in the typical form. Its coloration is a reddish-chestnut of varying intensity, often shading into yellowish tones on the upper part of the body whorl and consistently darker near the lip. The spire is often a deeper purplish-brown.

The suture is sometimes marked by a yellowish line, though this feature is not always present. The shell exhibits 2½ whorls in the protoconch, with the last one being very lightly, minutely, and unevenly striated. Subsequent whorls show rather coarse, low, and uneven wrinkles, making the surface rougher and less glossy compared to A. textilis.

The spire's outline contracts slightly near the summit, but the penultimate whorl noticeably bulges, particularly when viewed from the back. The axis is typically perforated, although in some narrower shells, the crevice may be nearly or entirely closed. A few older specimens feature a white callous nodule on the parietal wall, covered thinly by a semi-transparent or dirty-white film that is especially delicate at the outer edge.[2]

Distribution

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This species is endemic to Hawaii, occurring on Oahu island.

References

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  1. ^ Amastra decorticata Gulick, 1873. 12 December 2024. Retrieved through: World Register of Marine Species.
  2. ^ 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) Public Domain 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)
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