Coturnipes cooperi

Coturnipes cooperi

Harrison & Walker, 1977

Common name Enigmatic bird
Fossil group Birds
Order Aves incertae sedis
Family incertae sedis
Genus Coturnipes
Taxonomic status Taxonomically Uncertain
Geological age Ypresian

Summary

Coturnipes cooperi is one of the difficult London Clay bird species founded on a single end of a foot bone. It is based on a distal tarsometatarsus and has resisted secure placement within a modern order or family. Recent comparisons show that superficially similar Walton material should not simply be folded into this species.

The fossil therefore tells us little about ecology beyond showing a small bird capable of ordinary terrestrial perching or walking. Any more specific reconstruction of diet, habitat or locomotion would be speculative. The name remains useful for the diagnostic type morphology, but it should be applied conservatively.

Quick Identification

Look for: a distal tarsometatarsus matching the type in the relative widths and positions of the three toe trochleae and the distal vascular opening. Do not identify a worn small bird foot as Coturnipes merely from size.

Diagnostic Features

  • The species is founded on the distal end of a tarsometatarsus.
  • The arrangement of the distal trochleae forms the core of the diagnosis.
  • The second trochlea is narrower than in superficially similar Walton material compared with Danielsraptor.
  • The distal vascular foramen is positioned differently from the comparable Walton specimen formerly likened to Coturnipes.
  • No secure order level character combination has yet tied the holotype to a living avian radiation.

Fossil Details

Preservation
Only the distal foot is known securely. Abrasion, breakage or compression of the trochleae can prevent species level identification.

Similar Species

Recorded Fossil Sites

No fossil-site occurrences have yet been recorded for this species.

Last Reviewed
25 August 2026 Reviewed by Sam Harris