Abra splendens

Abra splendens

(J. de C. Sowerby, 1837)

Common name Clam
Fossil group Molluscs
Order Cardiida
Family Semelidae
Genus Abra
Taxonomic status Accepted
Geological age Ypresian

Summary

Abra splendens was a small clam that lived within the soft muddy seabed of the London Clay sea. It is interpreted as an infaunal deposit feeder, so rather than waiting for food to drift past, it gathered organic-rich material from the sediment surface while remaining protected beneath the seabed.

Living Abra use long siphons to reach the sediment-water interface while the shell remains buried. A similar way of life is a reasonable model for A. splendens: a small, mobile bivalve recycling fine organic matter in the mud and forming part of the food supply for larger predatory molluscs and fish.

Quick Identification

Look for: a small, thin, moderately inflated semelid clam with a smooth elongate-oval outline, fine concentric growth lines and only a weakly produced posterior end rather than a strongly rostrate shell.

Diagnostic Features

  • Shell is small, thin and elongate-oval in outline.
  • Valves are moderately inflated rather than strongly swollen.
  • Posterior end is only weakly produced or rostrate.
  • Exterior is smooth apart from fine concentric growth lines, without strong radial ribs.
  • Overall form is more inflated and less rostrate than the closely related London Clay Abra cygnea.

Fossil Details

Typical size
About 8.5 mm.
Fossil material
Shell, Internal Mould / Cast
Preservation
The thin shell is easily crushed or dissolved. Internal moulds may retain the general outline but lose the fine shell surface and hinge detail needed for a confident Species-level identification.

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