Edaphodon minor

Edaphodon minor

Ward, 1973

Common name Chimaeroid
Fossil group Sharks & Rays
Order Chimaeriformes
Family Edaphodontidae
Genus Edaphodon
Taxonomic status Accepted
Geological age Thanetian

Summary

Edaphodon minor was a smaller Palaeogene species of Edaphodon, a group of chimaeroids related to living chimaeras and ratfishes. Like other members of the genus, it carried persistent dental plates rather than rows of replaceable shark teeth. Dense tritor tissues within the plates formed hard working surfaces for crushing food.

The plates suggest it probably fed near the seabed on hard or resistant prey, likely including shelled invertebrates, although its exact diet is not directly known. Its feeding system belonged to the same specialised chimaeroid adaptation seen in larger Edaphodon species: durable plates for processing tough food rather than piercing teeth for seizing prey.

Quick Identification

Look for: a relatively small Edaphodon dental plate with the plate margin and tritor arrangement preserved; do not identify a small isolated tritor chip as E. minor solely because of its size.

Diagnostic Features

  • Dentition is formed from persistent tooth plates containing discrete tritors.
  • Plates are proportionally smaller and more lightly built than the large plates typical of Edaphodon bucklandi.
  • The arrangement and relative size of tritors varies predictably with plate position.
  • Plate margins and symphyseal geometry are required for secure comparison.
  • Size supports identification only when combined with the correct plate outline and tritor pattern.

Fossil Details

Typical size
Dental plates are centimetre-scale and generally smaller than comparable plates of Edaphodon bucklandi.
Fossil material
Tooth Plate
Preservation
Broken plates can appear deceptively small and should not be identified as E. minor on size alone. Retain a conservative Edaphodon sp. identification where the tritor pattern or plate outline is incomplete.

Similar Species

Recorded Fossil Sites

References

  • Dineley, D. & Metcalf, S. (1999). Fossil Fishes of Great Britain. Geological Conservation Review Series, 675 pp.. Joint Nature Conservation Committee, Peterborough View reference
  • Ward, D.J. (1973). The English Palaeogene Chimaeroid fishes. Proceedings of the Geologists' Association, 84(3), 315–330 View reference
  • Ward, D.J. (1978). The Lower London Tertiary (Palaeocene) succession of Herne Bay, Kent. Report of the Institute of Geological Sciences. Institute of Geological Sciences View reference
  • Ward, D.J. (1980). The distribution of sharks, rays and chimaeroids in the English Palaeogene. Tertiary Research, 3(1), 13–19 View reference
Last Reviewed
15 August 2026 Reviewed by Sam Harris