Regurgitated bones tell the story of hunting 290 million years ago

A unique fossil discovery in Thuringia provides the first direct insights into the feeding habits of early land predators.Researchers fromthe Museum für Naturkunde Berlin, HumboldtUniversity of Berlin and theCNRS (France)have discovered and analysed a fossilised regurgitate at the famous Bromackerfossil site. The findings have now been published in the international journal Scientific Reports.

The fossil consists of a compact mass of bone fragments and was initially thought to be fossilised faeces. However, detailed investigations revealed that it is a fossilised regurgitation – that is, indigestible food remains that a predator vomited up after eating. Such finds are extremely rare, especially on land. The Bromacker find is theoldest known evidence of such regurgitation from the Palaeozoic era and the first that can be clearly attributed to a terrestrial predator.

Using modern computed tomography, the researchers were able to visualise the bones contained within in three dimensions and assign them to individual animal species. The analysis revealed that the predator had eaten at least three different vertebrates of varying species and body sizes. These included two smaller, agile land animals and a significantly larger, herbivorous animal.

“For the first time, we can directly demonstrate which animals an early terrestrial predator consumed,” explains Arnaud Rebillard,lead author and PhD student at the Museum für Naturkunde Berlin. “Such direct evidence of dietary relationships is virtually unknown from this period.”

Only two large predators that lived in what is now Thuringia around 290 million years ago are possible culprits: Dimetrodon, known for its striking dorsal sail, and Tambacarnifex, an equally carnivorous early relative of mammals. Both are considered apex predators of their time. The find suggests that they hunted opportunistically and preyed on a wide variety of animals.

The discovery not only provides new insights into the behaviour of individual animals, but also offers a rare glimpse into the food webs of early terrestrial ecosystems. It demonstrates just how complex and diverse life on land already was hundreds of millions of years ago – long before dinosaurs dominated the Earth.

The Bromacker site within the UNESCO Global Geopark Thüringen Inselsberg – Drei Gleichen is regarded worldwide as one of the most important sites for early terrestrial vertebrates. The new findings underscore its outstanding importance for understanding the evolution of terrestrial ecosystems.

“The study is part of the BROMACKER collaboration funded by the German federal government and the State of Thuringia, and is a prime example of an innovative and interdisciplinary research and science communication programme that builds on decades of international cooperation and still has enormous potential for the future,” says senior author Prof. Jörg Fröbisch.

Publication: Rebillard,A., Jannel, A., Marchetti, L., MacDougall, M J., Hamann, C., Steyer, J-S., Fröbisch, J. (2026): Early Permian terrestrial apex predator regurgitalite indicates opportunistic feeding behaviour, Scientific Reports, doi: https://doi.org/10.1038/s41598-025-33381-0.