Labrophagus esocinus

Labrophagus esocinus

Casier, 1966

Common name Grinner / lizardfish
Fossil group Bony Fish
Order Aulopiformes
Family incertae sedis
Genus Labrophagus
Taxonomic status Accepted
Geological age Ypresian

Summary

Labrophagus esocinus was an aulopiform teleost from the London Clay with a long predatory head and very fine jaw dentition. Its teeth were better suited to holding small, soft-bodied prey than to crushing hard shells. As in many aulopiforms, an active carnivorous lifestyle involving small fishes or invertebrates is a reasonable inference from the feeding apparatus.

The known fossils are mostly three-dimensional skulls. Radiating sculpture on the cranial roof and strong striation on the quadrate give the head a distinctive texture, while the delicate teeth emphasise that feeding specialisation did not depend on a few enlarged fangs.

Quick Identification

Look for: an elongate aulopiform skull with radiating striations on the cranial roof, an especially strongly striated quadrate and dense rows of very fine pointed teeth along the jaws.

Diagnostic Features

  • Frontal and adjacent skull-roof bones carry strong radiating striations.
  • Quadrate is conspicuously sculptured with dense linear striae.
  • Jaw teeth are extremely fine, numerous and closely spaced.
  • Jaws are long and narrow rather than short and deep.
  • Anterior cranium tapers gradually toward the snout without a broad crushing palate.

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