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Amastra

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Amastra
Amastra elongata shell
Scientific classification Edit this classification
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 magna C. B. Adams, 1851
Synonyms
  • Achatinella (Amastra) H. Adams & A. Adams, 1855 superseded rank
  • Achatinella (Carinella) L. Pfeiffer, 1875 (invalid: junior homonym of Carinella Johnston, 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
  • Amastrella Sykes, 1900
  • Armiella Hyatt, 1911 · unaccepted > superseded rank
  • Cyclamastra Pilsbry & Vanatta, 1905
  • Helicter (Amastra) H. Adams & A. Adams, 1855 superseded rank
  • Heteramastra Pilsbry, 1911
  • Kauaia Sykes, 1900 (unaccepted rank)
  • Metamastra Hyatt & Pilsbry, 1911 superseded rank
  • Paramastra Hyatt & Pilsbry, 1911 ·

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

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 ormoderately 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

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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

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This genus is endemic to the Hawaiian Islands.

Species

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Species within the genus Amastra include:

Taxa inquirenda
  • Amastra amboinensis E. A. Smith, 1873
  • Amastra amicta E. A. Smith, 1873
  • Amastra citrea Sykes, 1896: synonym of Amastra mucronata citrea Sykes, 1896 (superseded rank)
  • Amastra lineolata (Newcomb, 1853)
  • Amastra longa Sykes, 1896
  • Amastra peasei E. A. Smith, 1873
  • Amastra seminuda Baldwin, 1906
  • Amastra villosa Sykes, 1896: synonym of Amastra hutchinsonii (Pease, 1862) (junior subjective synonym)

References

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  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) Public Domain This article incorporates text from this source, which is in the public domain.
  • Bank, R. A. (2017). Classification of the Recent terrestrial Gastropoda of the World. Last update: July 16, 2017
  • 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. pp. 1–248.{{cite book}}: CS1 maint: multiple names: authors list (link)
  • Schileyko, A.A. (1998). "Treatise on Recent terrestrial pulmonate molluscs. Part 1. Achatinellidae, Amastridae, Orculidae, Strobilopsidae, Spelaeodiscidae, Valloniidae, Cochlicopidae, Pupillidae, Chondrinidae, Pyramidulidae". Ruthenica (suppl. 2): 53.
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