Pliolophus barnesi

Pliolophus barnesi

Hooker, 2010

Common name Early Hoofed Mammal
Fossil group Mammals
Order Perissodactyla
Family Incertae sedis
Genus Pliolophus
Taxonomic status Accepted
Geological age Ypresian

Representative Specimens

Selected reference specimens illustrating this species from different geological units and fossil sites.

Identification Examples

Choose a fossil site to view photographed reference specimens.

Summary

Pliolophus barnesi was a small early perissodactyl belonging to the wider evolutionary radiation that ultimately produced horses, tapirs and rhinoceroses. Abbey Wood has yielded teeth and jaw material of this important Early Eocene mammal.

Historically Pliolophus was often discussed as an early horse relative. More recent phylogenetic work places it outside the true horse branch, making it particularly useful for understanding the very beginning of odd-toed ungulate evolution rather than simply treating it as an early horse.

Its remains form part of Abbey Wood’s important Early Eocene mammal fauna, while fossils assigned to the same species have also been reported from Early Eocene deposits in France.

Quick Identification

Look for: a small mammal cheek tooth with a low crown, rounded bumps and clearly raised ridges between them. Upper back teeth often have an extra small bump between the main ones, while the last lower molar has a noticeably enlarged rear section.

Diagnostic Features

  • Upper molars carry a conspicuous additional cusp between the principal cusps.
  • Main transverse ridge of the upper molars bends noticeably towards the outer side.
  • Third upper premolar has a particularly enlarged additional cusp.
  • On lower molars, the small rear cusp joins directly to one of the principal cusps.
  • Last lower molar has a proportionally enlarged posterior section compared with the preceding molars.

Fossil Details

Typical size
Small mammal. Individual cheek teeth are only a few millimetres across, so complete teeth can easily be overlooked when sorting material.
Fossil material
Tooth, Jaw, Limb Bone, Other Bone
Preservation
Most commonly encountered as isolated teeth and dental remains. Teeth from the Abbey Wood deposits can be very well preserved because dental enamel survives transport and burial better than most mammalian skeletal material. Jaw fragments and postcranial bones are also known.

Recorded Fossil Sites

References

  • Hooker, J. J. (2010). The mammal fauna of the Early Eocene Blackheath Formation of Abbey Wood, London. Monograph of the Palaeontographical Society, 164(634), 1–162. Palaeontographical Society, London View reference
Last Reviewed
17 August 2026 Reviewed by Sam Harris