Dentex pentagonalis
Dentex pentagonalis
Summary
Dentex pentagonalis was a sparid, or seabream relative, known in the London Clay from sagittal otoliths. Sparids are mostly coastal marine fishes with varied diets ranging from small invertebrates to fishes and hard-shelled prey. Because no associated jaws are known for this otolith species, a generalised benthic or near-bottom feeding ecology is more defensible than assigning it a particular diet.
The fossil is important as evidence for early sparid diversity in the Eocene. Its recognition depends on the complete outline and sulcus of the otolith, which record features of the inner ear that can be taxonomically informative even when skeletal remains are absent.
Quick Identification
Look for: a compact sparid sagittal otolith with a distinctly angular, approximately five-sided outline, a strongly convex inner face and a clear sulcus with a broadened anterior ostium and narrower posterior cauda.
Diagnostic Features
- Complete otolith has a conspicuously angular, pentagonal overall outline.
- Inner face is strongly convex compared with the flatter outer face.
- Anterior ostium is expanded and wider than the posterior sulcus.
- Cauda is narrower and more clearly channel-like than the ostium.
- Dorsal and posterior margins meet at distinct angular changes rather than forming a continuously rounded arc.
Fossil Details
Recorded Fossil Sites
London Clay Formation
References
- Steurbaut, E.; Nolf, D. (1988). Ypresian teleost otoliths from Belgium and northwestern France. Bulletin de la Société belge de Géologie, 97(3–4), 321–347 View reference
- Stinton, F. C. (1966). Fish otoliths from the London Clay. Faune ichthyologique du London Clay, 404–464. British Museum (Natural History), London View reference