Approximately 45 million years ago, the Diatryma, a flightless bird measuring 4.6 feet tall (1.40 meters), thrived in the Geiseltal area located in southern Saxony-Anhalt. A global group of researchers, led by Martin Luther University Halle-Wittenberg (MLU) and the Senckenberg Research Institute and Natural History Museum in Frankfurt, has published their findings on the bird’s exceptionally preserved skull in the journal Palaeontologia Electronica. This fossil was discovered in the 1950s at a former lignite mining site in Germany’s Geiseltal region. It was wrongly classified at first, which kept it somewhat obscure until it was identified again. The only other location where a similar skull fossil has been found is in the USA.
The Geiseltal area in Saxony-Anhalt is situated southwest of Halle and was recognized as a lignite mining site until 1993. Over the years, many remarkably preserved animal fossils have been excavated in this area. The Geiseltal Collection at MLU contains around 50,000 fossils and is regarded as a significant national heritage. These finds provide invaluable insights into animal evolution during the Eocene Epoch, roughly 45 million years ago. During this period, the Geiseltal was a warm, tropical swamp, hosting ancient horses, early tapirs, large terrestrial crocodiles, giant tortoises, various lizards, and numerous birds. Among these, some were unable to fly, with the largest being Diatryma, a plant-eating bird notable for its enormous beak and height of around 4.6 feet.
For many years, the existence of an almost entirely preserved Diatryma skull within the collection remained unknown. “It was initially misidentified as a crocodile skull,” explains Michael Stache, a geological preparator at MLU’s Central Repository of Natural Science Collections. Several years ago, Stache stumbled upon the fossil again, recognized the error, and proceeded to restore and analyze the skull fragment. He combined it with another item from the collection to recreate nearly the complete skull. Dr. Gerald Mayr from the Senckenberg Institute took a closer look at the specimen and confirmed its significance: the skull unmistakably belonged to a Diatryma. To date, only one other complete skull is known worldwide, housed at the American Museum of Natural History in the United States.
“This underscores how many fascinating discoveries in paleontology are found within museum collections. Just a few years ago, it was hard to believe that the Geiseltal Collection held such remarkable surprises,” Gerald Mayr remarked. Stache notes the growing scientific interest in the fossils, stating that researchers from Germany and abroad frequently visit MLU to study the items. “This research enhances our understanding of the Eocene Epoch in the Geiseltal, despite the fact that excavations finished long ago,” Stache pointed out. For example, up until a decade ago, it was believed that Diatryma preyed on prehistoric horses in the Geiseltal, but recent studies have indicated that this bird was actually herbivorous.
Currently, around 40 specimens of Diatryma exist within the Geiseltal Collection. “Diatryma was likely a rare visitor to the Geiseltal; otherwise, we would expect to find more fossils,” Stache concluded.
