52 Million Year Old Birds Found by Palaeontology Enthusiasts

Fossil bones of a leg (tarsometatarsus) and a wing (carpometacarpus) of a Messelornithidae of Egem (early Eocene) compared to those of Messelornis cristata of Messel, Germany (middle Eocene) (Photo: Sven Tränkner and Thierry Hubin)
04/04/2019
52 Million Year Old Birds Found by Palaeontology Enthusiasts
post by
Charlotte Degueldre

Thanks to the excavations carried out in Egem, West Flanders, by palaeontology enthusiasts we know more about the early Eocene birds of the North Sea Basin.

For more than 20 years, seven collectors have been digging into Egem's quarry in West Flanders. This clay quarry was used until a few years ago for the production of building bricks. The quarry is made up of marine sediments, mainly clays dating back to 52 million years ago. At that time, the region was covered by the North Sea.

The palaeontology enthusiasts were looking for fossil shark teeth. The screening method and equipment used by these fossil hunters allowed them to collect not only thousands of shark and ray teeth of all sizes, but also a few mammal teeth (including a marsupial, a primitive small horse and a bat) and, above all, several dozen bird bones.

Participatory paleontology

For palaeontologist Thierry Smith (Royal Belgian Institute of Natural Sciences), co-author of the study with palaeo-ornithologist Gerald Mayr of the Senckenberg Research Institute in Frankfurt, this is a perfect example of participatory science. "It took more than 20 years for these seven enthusiasts to collect this essential material. Professional palaeontologists would never have been given the means - in terms of personnel and finances - to search the site over such a long period of time! We owe them a lot.”

So rare and small

"Except in a few sites such as Messel where fossilization conditions were remarkable (a rapid burial in the mud of a volcanic lake, sheltered from air and light), fossil bones of birds of this period are very rare: hollow and light, they are very fragile and often dispersed before fossilization can even begin. However, in Egem, about a hundred bones and bone fragments were collected, half of which could be used for identification. "In addition, unlike the flattened fossils of Messel, those of Egem have not been compressed, which has made it possible to provide new osteological data for some species.”

Before joining our Institute's palaeontology collections, 53 bird bones were attributed to at least 20 different species. Most of them correspond to small birds. "They used very fine sieves in order not to lose the sometimes tiny teeth of sharks and rays. This is what allowed them to collect so many bones from birds that were so fragile and so small.”

Mostly continental birds

Among the identifiable specimens there were some seabirds, belonging to the Pelagornithidae family or "false-toothed birds " (it is in this family, now extinct, that the largest birds that have ever existed are found). But the majority were continental birds, probably living not far from the coast and whose bones were possibly carried to the sea by flooded rivers.

Among the continental specimens were Galliformes (order of hens, pheasants, turkeys...) and Messelornithidae (extinct family of Gruiformes close to the family Eurypygidae represented today only by the sunbittern), land birds, as well as Halcyornithidae (extinct family probably belonging to the order Psittaciformes which includes parakeets and parrots), Leptosomiformes (order represented today only by the cuckoo roller) and Coraciiformes (order of kingfishers, bee-eaters...), tree birds, and Apodiformes (order of martinets, fly birds...), insectivorous birds.

Note that the Messelornithidae of Egem are probably the ancestors of those of Messel (whose fossils are 48 million years old).

This study was published in Neues Jahrbuch für Geologie und Paläontologie.

 

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