Paraorthacodus eocaenus

Paraorthacodus eocaenus

(Leriche, 1902)

Common name Paraorthacodont shark
Fossil group Sharks & Rays
Order Hexanchiformes
Family Paraorthacodontidae
Genus Paraorthacodus
Taxonomic status Accepted
Geological age Thanetian

Summary

Paraorthacodus eocaenus was a small extinct shark known mainly from isolated teeth. It belongs to an ancient hexanchiform lineage outside the familiar living cow sharks and combines a principal cusp with smaller lateral cusplets.

Its dentition indicates a small predatory shark adapted to gripping relatively small prey. Behaviour and exact body form cannot be reconstructed directly from isolated teeth, so ecological interpretation should remain broad.

Quick Identification

Look for: a small multicuspid tooth with one dominant cusp, smaller lateral cusplets and a broad low root; fine basal crown folding is most useful when the surface is unworn.

Diagnostic Features

  • A dominant principal cusp is flanked by smaller lateral cusplets.
  • Cusplets form part of a continuous multicuspid crown rather than separate tooth crowns.
  • Fine vertical folding may be present around the crown base on well-preserved teeth.
  • Cutting edges are smooth rather than serrated.
  • The root is broad and low, and complete root proportions help separate the species from other small multicuspid sharks.

Fossil Details

Typical size
Teeth are small, generally millimetre-scale to about 1 cm across depending on jaw position.
Fossil material
Tooth
Preservation
Lateral cusplets, basal ornament and root margins are readily lost through abrasion. Worn or incomplete teeth should be identified conservatively.

Similar Species

Recorded Fossil Sites

Synonyms & Previous Names

Synechodus eocaenus

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. (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
22 August 2026 Reviewed by Sam Harris