Essexraja ypresiensis
Essexraja ypresiensis
Summary
Essexraja ypresiensis was a small skate-like ray living in the early Eocene seas of the Anglo-Belgian Basin. As a rajoid, it was probably associated with the seabed and fed on relatively small prey living on or close to the sediment.
Small crustaceans, worms and fishes are plausible components of its diet, although no direct gut contents or feeding traces are known. Its teeth show marked differences associated with jaw position and sex, indicating a more complex dentition than might be expected from such tiny isolated fossils.
The species is currently known from teeth rather than an articulated skeleton, so its body shape and precise ecology remain inferred. Even so, it provides important evidence that small skate-like rays were already diversifying in early Eocene marine ecosystems.
Quick Identification
Look for: a tiny rajoid tooth, roughly millimetric, with a rhomboid to elliptical crown base and a two-lobed holaulacorhize root; male-form teeth have a high pointed cusp, while female-form teeth are lower and blunter.
Diagnostic Features
- Teeth are very small, about 0.9–2.5 mm high in the type material.
- Male-form teeth have a pointed triangular cusp inclined lingually.
- Female-form teeth have a lower, flatter and much less pointed crown.
- Apron is absent and the lingual uvula is weak or absent.
- Root is holaulacorhize with two divergent lobes separated by a deep nutritive groove.
Fossil Details
Recorded Fossil Sites
No fossil-site occurrences have yet been recorded for this species.
References
- Reinecke, T.; Mollen, F.H.; Gijsen, B.; D’Haeze, B.; Hoedemakers, K. (2024). Batomorphs (Elasmobranchii: Rhinopristiformes, Rajiformes, Torpediniformes, Myliobatiformes) of the middle to late Ypresian, early Eocene, in the Anglo-Belgian Basin (south-western North Sea Basin) – a review and description of new taxa. Palaeontos, 35, 1–172 View reference