Amastra

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Phylum:Mollusca
Superfamily:Pupilloidea
Amastra
Amastra elongata shell
Scientific classification Edit this classification
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  • Achatinella (Amastra) H. Adams & A. Adams, 1855 superseded rank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 superseded rank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  • Helicter (Amastra) H. Adams & A. Adams, 1855 superseded rank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  • Metamastra Hyatt & Pilsbry, 1911 superseded rank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 used to thrive in wet or moderately wet forested areas.

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

Some individuals of remaining extant Amastra species were collected for captive breeding programs at the Bishop Museum and Snail Extinction Prevention Program. Reintroductions of some species are currently underway.

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

  • 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)

Synonyms

References

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