Alvania belli

Alvania belli
Shell of Alvania belli (holotype)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Superfamily:	Rissooidea
Family:	Rissoidae
Genus:	Alvania
Species:	†A. belli
Binomial name
†Alvania belli Harmer, 1920

Alvania belli is an extinct species of minute sea snail, a marine gastropod mollusc or micromollusk in the family Rissoidae.^[1]

Description

The length of the shell attains 2.5 mm, its diameter 1 mm.

(Original description) The minute, solid shell is ovate-conical. It contains 5 whorls. The body whorl is ventricose, much the largest, and measures three-fourths the total length. The whorls are obtusely angulate at the periphery and contracted below it. They are ornamented by strong and prominent longitudinal ribs, which terminate suddenly on the body whorl and are replaced by well-marked spiral ridges with fairly wide imterspaces. They also show exceedingly fine striae on the upper part of the shell. The spire is short and rapidly diminishes upwards towards a blunt and truncated protoconch. The suture is well marked and somewhat channelled. The aperture is large in proportion, expanded, angulate above and rounded below. The outer lip is thin. The lower part of the inner lip is reflected on the columella, which is nearly straight. ^[2]

Distribution

Fossils of this species were found in late Pliocene strata in St. Erth, Cornwall, Great Britain.

References

1. MolluscaBase eds. (2024). MolluscaBase. Alvania belli Harmer, 1920 †. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1027566 on 2024-02-06
2. Harmer F. W. (1920-1925). The Pliocene Mollusca of Great Britain, being supplementary to S.V. Wood's monograph of the Crag Mollusca. Vol. 2. Monographs of the Palaeontographical Society. 72(344): 485-652, pl. 45-52 (part 1, December 1920); 73(346): 653-704, pl. 53-56 (part 2, July 1921); 75(352): 705-856, pl. 57-64 (part 3, December 1923); 76(354): i-xiv, 857-900, pl. 65 (part 4, January 1925) This article incorporates text from this source, which is in the public domain.

External links

• Glibert, M. (1962). Les Mesogastropoda fossiles du Cénozoïque étranger des collections de l'Institut Royal des Sciences Naturelles de Belgique. Première partie. Cyclophoridae à Stiliferidae (inclus). Institut Royal des Sciences naturelles de Belgiques, Mémoires. Deuxième série. 69: 1-305