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

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

Description

edit

The length of the shell attains 3 mm, its diameter 2 mm.

(Original description) The minute, solid shell is ovate-conical. It contains 5 convex whorls. The body whorl is tumid and measures about two-thirds the total length. The three lower whorls are ornamented by well-marked longitudinal ribs, nearly straight, which die out or are cut off by strong spiral ridges, continuous to the base. The upper whorls are without sculpture. The spire is turreted, decreasing in size, compressed above, ending in a blunt rounded point. The suture is deep. The aperture is oval, rather short and expanded below. The outer and inner lip are thickened.[2]

Distribution

edit

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

References

edit