Amastra

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Amastra
Zoological Illustrations Achatinella acuta.jpg
Amastra elongata shell
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Stylommatophora
Superfamily: Pupilloidea
Family: Amastridae
Subfamily: Amastrinae
Genus: Amastra
H. Adams & A. Adams, 1855
Type species
Achatinella magnaC. B. Adams, 1851
Synonyms
  • Achatinella (Amastra)H. Adams & A. Adams, 1855 superseded rank
  • Achatinella (Carinella)L. Pfeiffer, 1875 (invalid: junior homonym of CarinellaJohnston, 1833 [Nemertea]; Kauaia is a replacement name)
  • Amastra (Amastra)H. Adams & A. Adams, 1855· accepted, alternate representation
  • Amastra (Amastrella)Sykes, 1900· accepted, alternate representation
  • Amastra (Armiella)Hyatt, 1911· accepted, alternate representation
  • Amastra (Cyclamastra)Pilsbry & Vanatta, 1905· accepted, alternate representation
  • Amastra (Heteramastra)Pilsbry, 1911· accepted, alternate representation
  • Amastra (Kauaia)Sykes, 1900· accepted, alternate representation
  • Amastra (Metamastra)Hyatt & Pilsbry, 1911· accepted, alternate representation
  • Amastra (Paramastra)Hyatt & Pilsbry, 1911· accepted, alternate representation
  • AmastrellaSykes, 1900
  • Armiella Hyatt, 1911 · unaccepted > superseded rank
  • CyclamastraPilsbry & Vanatta, 1905
  • Helicter (Amastra)H. Adams & A. Adams, 1855 superseded rank
  • HeteramastraPilsbry, 1911
  • KauaiaSykes, 1900 (unaccepted rank)
  • MetamastraHyatt & Pilsbry, 1911 superseded rank
  • ParamastraHyatt & Pilsbry, 1911 ·

Amastra is a genus of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Amastridae. [1]

Contents

Like many Hawaiian land snails, species in this genus have adapted to a specific ecological niche and have evolved in relative isolation. They are thriving in wet or moderately wet forested areas.

Many of the species in this genus have become extinct in recent times or have become critically endangered through habitat loss or predation. This loss is often highlighted as part of the broader biodiversity crisis faced by the Hawaiian Islands.

Description

The elongated shell is typically dextral (but some are sinistral), ranging from globose-conic to oblong-conic in shape. It may be umbilicate or imperforate. he shell surface might show growth striations or a fine malleation. The coloration varies, often appearing dull or dark, but sometimes light with a dull, darker, or yellowish cuticle. The shell consists of 5½ to 8 whorls, with the spire and apex conical in shape. The aperture is ovate, and the outer lip is not expanded but is often thickened internally. The columella features a spiral lamella that penetrates about half a whorl, and is present at all stages of growth observed. Above the lamella, the axis is slightly sinuous.

The species is viviparous. The jaw is vertically striate, and the teeth are arranged in nearly straight transverse rows, exhibiting the typical quadrate form. The central teeth are narrow with small, sinuous cusps. [2]

Distribution

This genus is endemic to the Hawaiian Islands.

Species

Species within the genus Amastra include:

Taxa inquirenda

Synonyms

References

  1. Amastra H. Adams & A. Adams, 1855 . 17 November 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. Retrieved 19 November 2024.{{cite book}}: CS1 maint: multiple names: authors list (link)PD-icon.svg This article incorporates text from this source, which is in the public domain .