Xampylodon loozi

Xampylodon loozi

(Vincent, 1876)

Common name Cow shark
Fossil group Sharks & Rays
Order Hexanchiformes
Family Hexanchidae
Genus Xampylodon
Taxonomic status Accepted
Geological age Thanetian

Summary

Xampylodon loozi was an extinct hexanchid cow shark previously placed in Notidanodon. It is known mainly from isolated teeth, with the lower dentition developing the characteristic saw-like multicuspid form associated with hexanchids.

The teeth indicate a cutting and grasping predator. Strong differences between upper and lower teeth mean that jaw position must be considered before comparing isolated specimens.

Quick Identification

Look for: a cow-shark tooth with a main acrocone followed by distally inclined cusplets, especially the saw-like lower teeth; the root is deep and the cusplet pattern is more informative than an isolated broken cusp.

Diagnostic Features

  • Lower teeth are multicuspid and develop a distinctly saw-like profile.
  • The main acrocone and associated cusplets are inclined distally.
  • Mesial cusplets are much smaller than the distal cusplets.
  • The mesial cutting edge of the main cusp is convex.
  • The root is comparatively deep, helping separate Xampylodon from the traditional Notidanodon concept.

Fossil Details

Typical size
Teeth are centimetre-scale, with substantial size and shape differences between jaw positions.
Fossil material
Tooth
Preservation
The smaller cusplets are commonly broken and lower teeth can lose the saw-like outline through wear. Upper and lower teeth should not be compared as if they were one tooth form.

Similar Species

Recorded Fossil Sites

Synonyms & Previous Names

Notidanodon loozi

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