Amastra conifera

Amastra conifera
Shell of Amastra conifera (holotype)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Stylommatophora
Family:	Amastridae
Genus:	Amastra
Species:	A. conifera
Binomial name
Amastra conifera E. A. Smith, 1873
Synonyms
Amastra (Amastra) coniferaE. A. Smith, 1873 alternative representation

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

Description

The length of the shell attains 17 mm, its diameter 9 mm

The shell is ovate-conic, dextral, and delicately striated with growth lines. Its coloration is a very pale reddish hue, partially covered by a brownish-olivaceous epidermis. It comprises 6½ whorls that are slightly convex. The initial 2½ to 3 whorls are reddish, prominently radially sulcate, and adorned with a distinct spiral cord at the base.

The suture is simple and unadorned. The aperture is whitish, while the peristome is thin, blackish, and slightly thickened. The columellar fold is slender and well-defined.

The aperture is strongly oblique, with a thin outer lip. The columella is straight, its edge narrowly reflexed and adnate above, bearing a small, very oblique fold.

All specimens are imperforate and thin, with spire outlines that are either straight or slightly contracted near the apex. The coloration varies as follows:

• Pale Variation: Very pale reddish, transitioning to a lighter, creamy tone on the last whorl.
• Two-Tone Variation: Spire is a darker reddish-brown with a distinct white sutural border, while the body whorl is cream-white.
• Creamy Variation: Uniform cream-white throughout, with only the embryonic whorls showing a reddish-brown hue.

The thin, olive or olive-brown cuticle is typically absent from most of the shell above the body whorl. Where retained on the penultimate whorl and the front of the body whorl, it features angular dark patterns or light mottling on a darker ground, forming a network. On the latter part of the body whorl, the cuticle becomes continuous except where worn.

The apex exhibits the characteristic costate and carinate structure. The body whorl is angular at the periphery, with the angle generally sharp and distinct in front, though it can occasionally appear subdued.

Older shells may develop a very thin callus within the lip, but this feature is typically faint. In the type specimen, the edge of the lip retains a blackish cuticular margin, which is absent in other examples. ^[2]

Distribution

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

References

1. Amastra conifera E. A. Smith, 1873 . 11 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. This article incorporates text from this source, which is in the public domain .

• Gulick, J. T. & Smith, E. A (1873). "Descriptions of new species of Achatinellinae". Proceedings of the Zoological Society of London. 1873: 85. Retrieved 11 December 2024.
• 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.