Argilloberyx prestwichae

Argilloberyx prestwichae

Casier, 1966

Common name Soldierfish / pricklefish
Fossil group Bony Fish
Order Beryciformes
Family incertae sedis
Genus Argilloberyx
Taxonomic status Accepted
Geological age Ypresian

Summary

Argilloberyx prestwichae was a beryciform teleost from the London Clay sea. The skull narrows strongly toward the snout and carries a wide mouth armed with fine teeth, a combination consistent with a predator taking small fishes or mobile invertebrates. This feeding interpretation is based on cranial and dental anatomy; direct dietary evidence is not known.

Beryciform fishes were an important component of early Cenozoic marine faunas, and Argilloberyx adds to that diversity. It is chiefly known from three-dimensional cranial fossils, so the head is much better documented than the body. The tapered facial region and broad gape give the animal a recognisable feeding architecture even though its complete silhouette remains uncertain.

Quick Identification

Look for: a beryciform skull that narrows conspicuously in front of the orbits, with a broad gape and rows of very fine pointed teeth; the anterior cranium forms a much slimmer snout than the posterior skull.

Diagnostic Features

  • Nasal and preorbital region narrows strongly toward the snout.
  • Mouth opening is broad relative to the width of the anterior cranium.
  • Jaw teeth are numerous, fine and closely spaced rather than large and isolated.
  • Posterior skull is appreciably broader than the snout region.
  • Cranial bones are relatively thin and finely sculptured compared with the heavy dentition of crushing fishes.

Fossil Details

Preservation
London Clay fish skulls are commonly incomplete, compressed, pyritised or enclosed in concretions. Thin cranial margins and projecting processes are easily lost, and separated bones can be difficult to orient; species-level identification is strongest when several adjoining diagnostic bones are preserved together.

Recorded Fossil Sites

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

References

  • Casier, E. (1966). Faune ichthyologique du London Clay. 496 pp.. Trustees of the British Museum (Natural History), London View reference
  • Friedman, M.; Beckett, H. T.; Close, R. A.; Johanson, Z. (2016). The English Chalk and London Clay: two remarkable British bony fish Lagerstätten. Geological Society, London, Special Publications, 430(1), 165–200. Geological Society of London, London View reference
Last Reviewed
20 August 2026 Reviewed by Sam Harris