Palaeophytocrene ambigua

Palaeophytocrene ambigua

Reid et Chandler

Fossil group Plants
Order Icacinales
Family Icacinaceae
Genus Palaeophytocrene
Taxonomic status Accepted
Geological age Ypresian

Summary

Palaeophytocrene ambigua was a member of the Phytocreneae branch of Icacinaceae, recognised from a fruit stone with large pits. Those pits are the outer expression of broad funnel-shaped tubercles projecting into the seed cavity, each pierced by a relatively straight canal. The architecture is therefore genuinely three-dimensional and not simply a pitted shell surface.

The known London Clay specimens are incomplete locule casts with remnants of the endocarp, so the full external sculpture is unknown. Even so, the tubercle-and-canal construction securely links the fossil to Phytocreneae. It differs from P. foveolata in having fewer, larger pits and more strongly funnel-shaped internal projections. A resemblance to the living genus Miquelia has been discussed, but the fossil evidence does not justify replacing the established fossil genus.

Quick Identification

Look for: a relatively large locule cast around 22 mm long with a small number of large pit impressions arranged in loose longitudinal rows. The pits correspond to broad funnel-shaped tubercles projecting into the locule; CT or broken internal surfaces are especially useful.

Diagnostic Features

  • Endocarp/locule form is bisymmetrical, unilocular and lenticular in cross-section.
  • Large pits are arranged in irregular longitudinal series, roughly 8–9 along the length and 4–5 across the width.
  • Each pit corresponds internally to a broad funnel-shaped tubercle projecting into the locule.
  • Canals within the tubercles are relatively parallel-sided.
  • The pit/tubercle units are larger and fewer than in Palaeophytocrene foveolata.

Fossil Details

Typical size
Locule cast about 22 mm long and roughly 12.5–14.5 mm wide.
Fossil material
Seed, Fruit
Preservation
Only a small number of incomplete specimens are known, mainly as locule casts with partial endocarp. Loss of the outer wall prevents assessment of any fine external sculpture, and abrasion may truncate the projecting tubercles.

Similar Species

Recorded Fossil Sites

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

References

  • Eleanor Mary Reid; Marjorie Elizabeth Jane Chandler. (1933). The London Clay Flora. . British Museum (Natural History), London View reference
  • Gregory W. Stull; Neil F. Adams; Steven R. Manchester; Dan Sykes; Margaret E. Collinson. (2016). Revision of Icacinaceae from the Early Eocene London Clay flora based on X-ray micro-CT. Botany, 94(9), 713–745 View reference
  • Margaret E. Collinson; Neil F. Adams; Steven R. Manchester; Gregory W. Stull; Fabiany Herrera; Selena Y. Smith; Mary J. Andrew; Paul Kenrick; Dan Sykes. (2016). X-ray micro-computed tomography (micro-CT) of pyrite-permineralized fruits and seeds from the London Clay Formation (Ypresian) conserved in silicone oil: a critical evaluation. Botany, 94(9), 697–711 View reference
Last Reviewed
26 August 2026 Reviewed by Sam Harris