Discorbis chapmani
Discorbis chapmani
Common name
Foraminifer
Fossil group
Foraminifera
Order
Rotaliida
Family
Discorbidae
Genus
Discorbis
Taxonomic status
Accepted
Geological age
Ypresian
Summary
Discorbis chapmani was a small benthic rotaliid foraminifer with a trochospiral calcitic test. It likely lived at the sediment-water interface or on small firm particles, using pseudopodia to graze bacteria and collect fine organic food.
The organism itself was a single cell, but the fossil is its microscopic test. In the 2026 Hampshire Basin study this taxon occurs within the London Clay Formation assemblage used to construct the first foraminiferal zonation of the formation.
Quick Identification
Look for: a small discoidal to low trochospiral test with a flattened spiral side, more open umbilical side and a rounded lobulate margin.
Diagnostic Features
- Test low trochospiral and broadly discoidal.
- Spiral side comparatively flat and shows successive whorls.
- Umbilical side more inflated or open than the spiral side.
- Final chambers produce a gently lobulate peripheral outline.
- Aperture occurs near the umbilical margin of the final chamber.
Fossil Details
Typical size
Microscopic; generally sub-millimetric.
Fossil material
Foraminiferal Test
Preservation
London Clay foraminiferal tests may be etched, crushed, stained or filled with matrix, and the 2026 study notes poorer preservation in parts of the succession. Fine apertural and sutural characters can disappear with corrosion; incomplete tests should be left at genus or higher rank.
Similar Species
Recorded Fossil Sites
No fossil-site occurrences have yet been recorded for this species.
References
- Hart, M. B.; Alex-Sanders, M. E. A.; Smart, C. W. (2026). Can the distribution of foraminifera locate the Early Eocene Climatic Optimum (EECO) and Middle Eocene Climatic Optimum (MECO) events in the Eocene succession of the Isle of Wight (UK)?. Journal of Micropalaeontology, 45(1), 315–334 View reference
Last Reviewed
20 August 2026
Reviewed by
Sam Harris