Volvulella radius

Volvulella radius

(Deshayes, 1862)

Common name Headshield snail
Fossil group Molluscs
Order Cephalaspidea
Family Rhizoridae
Genus Volvulella
Taxonomic status Accepted
Geological age Ypresian

Summary

Volvulella radius was a minute marine headshield snail that lived on or just within soft seabed sediment. Related forms are mobile prey feeders, making an active benthic lifestyle the most likely interpretation for this tiny London Clay animal.

Its exact prey is unknown, but it probably hunted very small motile animals in the sediment-surface community. The ecological interpretation is based on the biology of related headshield snails because the fossil preserves the shell rather than the soft feeding anatomy.

Quick Identification

Look for: a tiny slender, spindle- to olive-shaped shell with a distinctly extended pointed apex, a long narrow aperture, a rounded columellar edge and a small basal umbilicus.

Diagnostic Features

  • Shell is slender and elongate-ovoid, with its greatest width near mid-shell.
  • The apex is distinctly extended and pointed.
  • The adult shell is involute, without an exposed multiwhorled spire.
  • The columellar edge is rounded and only weakly thickened.
  • A small umbilicus is present at the basal end of the shell.

Fossil Details

Typical size
About 2.5–3 mm.
Fossil material
Shell, Internal Mould / Cast
Preservation
Because the shell is extremely small and smooth, crushing can alter its proportions and abrasion can erase subtle sculpture. The complete outline and aperture are more useful than isolated fragments.

Similar Species

Recorded Fossil Sites

No fossil-site occurrences have yet been recorded for this species.

References

  • Jeffery, P.; Tracey, S. (1997). The Early Eocene London Clay Formation mollusc fauna of the former Bursledon Brickworks, Lower Swanwick, Hampshire. Tertiary Research, 17(3–4), 75–137 View reference
Last Reviewed
15 August 2026 Reviewed by Sam Harris