Zanthopsis dufouri

Zanthopsis dufouri

(H. Milne Edwards in d'Archiac, 1850)

Common name Crab
Fossil group Crustaceans
Order Decapoda
Family Zanthopsidae
Genus Zanthopsis
Taxonomic status Accepted
Geological age Ypresian

Summary

Zanthopsis dufouri was a heavily armoured true crab with a broad, powerful body. It probably lived as a generalist predator and scavenger on the seabed, using strong claws to handle food while its thick carapace protected it from attack.

The London Clay contains several species of Zanthopsis, suggesting that robust crabs of this general type were successful members of the ecosystem. They would have competed with other crabs and lobsters for food while also serving as prey for larger marine predators.

Quick Identification

Look for: a broad robust Zanthopsis carapace with strong dorsal sculpture and regional relief; compare the complete margins and ornament directly with Z. leachii, Z. nodosa and Z. unispinosa.

Diagnostic Features

  • Carapace broad and robust.
  • Dorsal regions are strongly sculptured and well defined.
  • Surface relief is pronounced across the gastric and branchial areas.
  • Marginal form differs from the nodose and strongly spined patterns of other Zanthopsis species.
  • Species-level identification requires the combined regional pattern, ornament and margins.

Fossil Details

Typical size
Centimetre-scale robust crab; exact species-wide range is not securely established.
Fossil material
Carapace, Claw / Chela
Preservation
Zanthopsis carapaces can be robust but their lateral and frontal margins are frequently incomplete. Abrasion may blur the species-specific sculpture and regional relief.

Similar Species

Recorded Fossil Sites

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

Synonyms & Previous Names

Cycloxanthus dufouri

References

  • J. S. H. Collins; C. J. T. Mellish; A. J. Ross; P. R. Crabb; S. K. Donovan. (2020). A guide to the fossil Decapoda (Crustacea: Axiidea, Anomura, Brachyura) of the British Isles. Proceedings of the Geologists' Association, 131(1), 19–50 View reference
  • Thomas Bell. (1857). A monograph of the fossil malacostracous Crustacea of Great Britain. Part I. Crustacea of the London Clay. Monograph of the Palaeontographical Society, 10, i–viii, 1–44. Palaeontographical Society, London View reference
Last Reviewed
15 August 2026 Reviewed by Sam Harris