Described September 26 in the journal Palaeontology, the skull belongs to Dasornis emuinus, a bony-toothed bird, or pelagornithid, and was discovered in the London Clay, which lies under much of London, Essex and northern Kent in SE England. The occurrence of bony-toothed birds in these deposits has been known for a long time, but the new fossil is one the best skulls ever found, and preserves previously unknown details of the anatomy of these strange birds.
With a five metre wingspan, these huge birds were similar to albatross in their way of life. Albatross have the largest wingspan of any living bird, but that of Dasornis was over a meter and half greater. Despite these similarities, the latest research suggests that the closest living relatives of Dasornis and its fossil kin are ducks and geese.
“Imagine a bird like an ocean-going goose, almost the size of a small plane! By today’s standards these were pretty bizarre animals, but perhaps the strangest thing about them is that they had sharp, tooth-like projections along the cutting edges of the beak” explains Gerald Mayr, expert palaeornithologist at the German Senckenberg Research Institute and author of the report.
These were not true teeth but bony projections of the beak, functioning as teeth, probably to catch fish.
Birds no longer produce teeth: they have the genes to do so but teeth do not develop in the absence of bone. So Dasornis developed a functional substitute. The Dasornis’ tooth is like the panda’s thumb.
- Mayr et al. A skull of the giant bony-toothed bird Dasornis (Aves: Pelagornithidae) from the Lower Eocene of the Isle of Sheppey. Palaeontology, 2008; 51 (5): 1107 DOI: 10.1111/j.1475-4983.2008.00798.x