Chimaera eophantasma
Chimaera eophantasma
Common name
Chimaeroid
Fossil group
Sharks & Rays
Order
Chimaeriformes
Family
Chimaeridae
Genus
Chimaera
Taxonomic status
Accepted
Geological age
Thanetian
Summary
Chimaera eophantasma was an extinct Palaeogene chimaeroid and one of the specialised holocephalans known mainly from dental plates. Living chimaeras are bottom-associated fishes, and the plate-like dentition of this species likewise indicates a feeding system very different from that of sharks.
Its dental plates were adapted for crushing and shearing rather than piercing.
Quick Identification
Look for: a compact chimaeroid tooth plate with its tritor pattern and plate margins preserved; compare palatine, mandibular and vomerine positions separately because isolated tritor fragments are not enough for secure species identification.
Diagnostic Features
- Dentition consists of persistent tooth plates rather than discrete replaceable teeth.
- The plate contains discrete hypermineralised tritor areas used as crushing surfaces.
- Different jaw positions have distinct plate outlines and tritor arrangements.
- Complete margins and the relationship between tritors are more diagnostic than isolated tissue fragments.
- The combination of plate position, outline and tritor geometry is required to distinguish the species from other Palaeogene chimaeroids.
Fossil Details
Typical size
Dental plates are centimetre-scale, with size depending on plate position and completeness.
Fossil material
Tooth Plate
Preservation
Plate fragments are common and may retain only one tritor. Species-level attribution should be avoided when the original plate position or surrounding outline is lost.
Similar Species
Recorded Fossil Sites
Beltinge Fish Bed
Upnor Formation
Confirmed
References
- Dineley, D. & Metcalf, S. (1999). Fossil Fishes of Great Britain. Geological Conservation Review Series, 675 pp.. Joint Nature Conservation Committee, Peterborough View reference
- Ward, D.J. (1973). The English Palaeogene Chimaeroid fishes. Proceedings of the Geologists' Association, 84(3), 315–330 View reference
- Ward, D.J. (1978). The Lower London Tertiary (Palaeocene) succession of Herne Bay, Kent. Report of the Institute of Geological Sciences. Institute of Geological Sciences View reference
- Ward, D.J. (1980). The distribution of sharks, rays and chimaeroids in the English Palaeogene. Tertiary Research, 3(1), 13–19 View reference
Last Reviewed
15 August 2026
Reviewed by
Sam Harris