Burnhamia daviesi
Burnhamia daviesi
Summary
Burnhamia daviesi was an unusual early relative of the mobulid rays, the group that today includes manta and devil rays. Its importance extends beyond the London Clay because it helps document the evolutionary transition from the heavy crushing dentitions of many eagle-ray relatives towards the specialised feeding systems of plankton-feeding mobulids.
Unlike the broad grinding plates of strongly shell-crushing rays, the dentition of Burnhamia shows reduced durophagous specialisation. Detailed study of its articulated jaws has been interpreted as evidence that the lineage was moving towards feeding on much smaller prey and possibly towards pelagic planktivory.
The exact feeding mechanism of B. daviesi cannot be reconstructed with certainty, but its anatomy makes it one of the more informative early rays for understanding how the highly specialised open-water feeding ecology of later mobulids may have evolved.
Quick Identification
Look for: very broad, low plate teeth arranged in several anteroposterior rows; median teeth are about four times wider than long, and the crowns show transverse channel-like relief with interlocking front and rear margins.
Diagnostic Features
- Dentition contains nine anteroposterior tooth series in the type material.
- Median teeth are strongly transverse, about four times broader than long.
- First and second lateral rows are also markedly wider than long, with outer rows progressively less elongate.
- Crown surfaces show transverse channel-like relief and specialised anteroposterior interlocking.
- Root bears anteroposterior grooves and ridges beneath the thin crown.
Fossil Details
Recorded Fossil Sites
London Clay Formation
References
- Hovestadt, D.C.; Hovestadt-Euler, M. (2013). Generic Assessment and Reallocation of Cenozoic Myliobatinae based on new information of tooth, tooth plate and caudal spine morphology of extant taxa. Palaeontos, 24, 1–66 View reference
- Rayner, D.; Mitchell, T.; Rayner, M. (2009). London Clay Fossils of Kent and Essex. 228 pp.. Medway Fossil and Mineral Society, Rochester, Kent View reference
- 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
- Underwood, C.J.; Kolmann, M.A.; Ward, D.J. (2017). Paleogene origin of planktivory in the Batoidea. Journal of Vertebrate Paleontology, 37(3), e1293068 View reference