Eocypselus paulomajor

Eocypselus paulomajor

Mayr & Kitchener, 2024

Common name Swift relative
Fossil group Birds
Order Apodiformes
Family Eocypselidae
Genus Eocypselus
Taxonomic status Accepted
Geological age Ypresian

Summary

Eocypselus paulomajor was a stem swift relative of intermediate size within the London Clay Eocypselus assemblage. Its skeleton records an early stage in apodiform evolution before the extreme wing specialisations of living swifts and hummingbirds had developed.

It was probably a capable aerial insectivore or perch launched insect catcher, but the exact balance between continuous aerial feeding and more generalised flight is inferred. The species is differentiated from its congeners through the proportions and details of associated bones rather than by a single collector friendly character.

Quick Identification

Look for: an associated Eocypselus skeleton with proportions larger than the smallest congeners but below E. grandissimus, together with the expected eocypselid joint morphology. Isolated fragments rarely justify a species name.

Diagnostic Features

  • The species shows the characteristic eocypselid combination of early apodiform skeletal features.
  • Its overall size is greater than the smallest London Clay Eocypselus forms.
  • It remains smaller than E. grandissimus in the diagnostic associated material.
  • The wing proportions are primitive relative to crown swifts and hummingbirds.
  • Species separation depends on a multibone proportional and osteological comparison with the other London Clay Eocypselus species.

Fossil Details

Preservation
Small differences among congeners mean that compression, incomplete ends and juvenile or individual variation must be considered before species assignment.

Similar Species

Recorded Fossil Sites

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

Last Reviewed
16 August 2026 Reviewed by Sam Harris