Volvarina Explained

Volvarina is a genus of small to very small sea snails, marine gastropod molluscs in the family Marginellidae, the margin shells.

Taxonomy

The difference between the genera Volvarina and Prunum is not clearly delineated and is based on morphological differences in the shells. Larger species with a strong callus are classified under Prunum, while the slender species with a thin callus are classified under Volvarina. Many species with characteristics that fall between the two extremes are ambiguous. Until at least 2010 there was no phylogenetic analysis to substantiate this classification. Volvarina is paraphyletic in relation to Prunum and Hyalina. Their status remains uncertain.

Description

The smooth or glossy shells are very small. They have a conical or cylindrical shape. The spire is usually low or sometimes slightly elevated. The anal sinus is absent. The outer lip is smooth or slightly incrassate. The inner lip shows three of four plaits; some species show a weaker fifth or sixth fold. They occupy about half the length of the aperture.

Distribution

The genus is cosmopolitan with most species in warm and temperate seas.

Species

Species within the genus Volvarina include:

Synonyms

References

External links

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