Alvania erecta

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

Alvania erecta 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 is 2 mm (0.079 in), and its diameter is 1 mm (0.039 in).

(Original description) The minute shell is ovate-conical. It contains 6 convex whorls. The body whorl is rather tumid and much the largest. The shell is ornamented by numerous fine longitudinal ribs which die out at the periphery, and by delicate spiral lines which become somewhat stronger below it. The suture is distinct and slightly channelled, with a spiral line immediately above it. The spire is short, regularly diminishing in size towards an acute point. The oval aperture is rather small. The outer lip is gently rounded, incurved above and not much expanded. The inner lip is somewhat reflected. The peristome is continuous. [2]

Distribution

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

References

1. MolluscaBase eds. (2024). MolluscaBase. Alvania erecta Harmer, 1920 †. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1027568 on 2024-02-07
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.