Jupiteria prisca

Jupiteria prisca

(Deshayes, 1858)

Common name Clam
Fossil group Molluscs
Order Nuculanida
Family Yoldiidae
Genus Jupiteria
Taxonomic status Accepted
Geological age Ypresian

Summary

Jupiteria prisca was a minute clam that probably lived as a mobile shallow burrower in the soft London Clay seabed. Its closest ecological comparison is with small protobranch bivalves that gather food directly from organic-rich sediment rather than relying only on particles suspended in the water.

It was therefore most likely a deposit feeder, using palp proboscides to collect and sort fine material from the mud. This feeding style is inferred from related living forms because the fossil preserves the shell rather than the soft anatomy.

Quick Identification

Look for: a tiny, high-convex and distinctly inequilateral taxodont valve with a rounded anterior end, a narrowed posterior end, a gently convex posterior dorsal margin, and a conspicuous central ligament pit between the two tooth rows.

Diagnostic Features

  • The shell is proportionately high and strongly convex.
  • The valve is distinctly inequilateral, with the posterior end narrowed or shortly produced.
  • The posterior dorsal margin is gently convex.
  • The hinge carries long rows of fine taxodont teeth on both sides of the umbo.
  • A large central ligamental pit or resilifer is conspicuous within the tiny hinge.

Fossil Details

Typical size
About 3.5–4 mm.
Fossil material
Shell, Internal Mould / Cast
Preservation
The pointed end, dorsal margin and fine hinge teeth are easily damaged. Internal moulds may preserve the gross outline but not the tooth rows needed for a strong Species-level identification.

Similar Species

Recorded Fossil Sites

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

Synonyms & Previous Names

Yoldiella prisca

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
  • Schnetler, K. I. (2001). The Selandian (Paleocene) mollusc fauna from Copenhagen, Denmark: the Poul Harder 1920 collection. Geology of Denmark Survey Bulletin, 37, 1–85 View reference
Last Reviewed
20 August 2026 Reviewed by Sam Harris