Glyphithyreus wetherelli

Glyphithyreus wetherelli

(Bell, 1858)

Common name Mud Crab
Fossil group Crustaceans
Order Decapoda
Family Panopeidae
Genus Glyphithyreus
Taxonomic status Accepted
Geological age Ypresian

Summary

Glyphithyreus wetherelli was a mud-dwelling true crab that lived on the soft sea floor. Like many modern mud crabs, it was probably an opportunistic omnivore, feeding on worms, small molluscs, other crustaceans and carrion encountered while moving over or digging into the sediment.

The London Clay was deposited in a warm marine setting with extensive soft-bottom habitats, so a crab adapted to muddy ground would have had plenty of suitable territory. It would have occupied the busy middle of the food web, hunting smaller animals while avoiding larger fish and crustaceans.

Quick Identification

Look for: a broad panopeid-style carapace with a compact front, defined dorsal regions and well-developed side margins; confirm the complete outline rather than relying on a single claw.

Diagnostic Features

  • Carapace broad and compact in dorsal view.
  • Lateral margins are well developed and form a strong part of the outline.
  • Dorsal regions are visible but not as coarsely tuberculate as Dromilites belli.
  • Overall form is less elongate than raninid frog crabs.
  • Species-level identification should combine carapace outline, margins and dorsal regions.

Fossil Details

Typical size
Centimetre-scale carapace; a reliable population range is not established.
Fossil material
Carapace, Claw / Chela
Preservation
Lateral margins and frontal structures are commonly chipped. Abrasion or internal-mould preservation may weaken the surface features needed for comparison.

Similar Species

Recorded Fossil Sites

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