Volvulella lanceolata
Volvulella lanceolata
Summary
Volvulella lanceolata was a minute headshield snail that probably moved through or across the uppermost soft sediment of the London Clay seabed. Living members of the group are mobile benthic animals, so this species was likely an active feeder rather than a permanently fixed or suspension-feeding mollusc.
Its exact prey is not preserved, but comparison with related headshield snails suggests that it probably took very small benthic animals. At only a few millimetres long, it occupied a tiny-predator niche within the sediment-surface community.
Quick Identification
Look for: a tiny olive- to lance-shaped shell with the spire hidden in an apical slit, a posterior beak projecting beyond the apex, deep unequal spiral grooves concentrated toward the ends, and a very narrow aperture that widens anteriorly.
Diagnostic Features
- The last whorl envelops the shell, with the spire concealed at the bottom of a narrow apical slit.
- The shell is more attenuated posteriorly than anteriorly and ends posteriorly in a projecting rostrum.
- Deep, spaced and unequal spiral striae become more closely set around the anterior umbilical slit.
- The aperture is extremely narrow posteriorly but widens anteriorly to a rounded, unnotched end.
- The columellar margin is thick and twisted, partly reflected over the umbilical slit and bearing one median fold.
Fossil Details
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