Raninoides glabra
Raninoides glabra
Common name
Frog Crab
Fossil group
Crustaceans
Order
Decapoda
Family
Raninidae
Genus
Raninoides
Taxonomic status
Accepted
Geological age
Ypresian
Summary
Raninoides glabra was a frog crab, a streamlined crab adapted for life in soft sediment. Living raninids often bury themselves rapidly in sand or mud with only part of the body exposed, using the sediment both as camouflage and as protection.
From this hidden position a frog crab can seize passing prey or emerge to forage across the bottom. R. glabra therefore represents a very different London Clay lifestyle from exposed swimming crabs or sponge-carrying dromiids.
Quick Identification
Look for: a smooth, elongate frog-crab carapace with a streamlined raninid outline and relatively subdued dorsal ornament; compare directly with Raninoides gottschei.
Diagnostic Features
- Carapace distinctly elongate rather than broad and transversely expanded.
- Dorsal surface comparatively smooth for a London Clay frog crab.
- Outline is streamlined, consistent with a burrowing raninid body form.
- Frontal and orbital region has the characteristic raninid construction.
- Species-level separation from Raninoides gottschei requires the complete outline and dorsal surface character.
Fossil Details
Typical size
Centimetre-scale carapace; exact species-wide range is not securely established.
Fossil material
Carapace, Claw / Chela
Preservation
The long carapace may crack across its width and the frontal region is commonly incomplete. Surface wear can make both Raninoides species appear deceptively similar.
Similar Species
Recorded Fossil Sites
No fossil-site occurrences have yet been recorded for this species.
Synonyms & Previous Names
Palaeocorystes glabra; Raninella glabra; Raninellopsis glabra
References
- Hiroaki Karasawa; Rodney M. Feldmann; Carrie E. Schweitzer; Javier Luque. (2014). Phylogeny and classification of Raninoida (Decapoda: Brachyura). Journal of Crustacean Biology, 34(2), 216–272 View reference
- 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
Last Reviewed
16 August 2026
Reviewed by
Sam Harris