Oldest fossilized dinosaur vomit discovered in Germany
About 290 million years ago, a carnivorous dinosaur stomping around in present-day Germany had a stomach ache. The Paleozoic predator eventually vomited up its stomach contents and hopefully continued living its best dinosaur life. Unlike most ancient regurgitated meals, this particular mixture of half-eaten prey and digestive bacteria has successfully fossilized into what is called a regurgitation.
In 2021, paleontologists discovered this extremely rare find while working at the famous Permian excavation site of Bromacker, about 250 kilometers southwest of Berlin. As they detail in a study published on January 30 in the journal Scientific reportsthe fossilized regurgitation is the oldest specimen of its species and contains a lot of information about the still often mysterious food chain of terrestrial dinosaurs.
What is regurgitation?
The bones tell researchers a lot about ancient species, but they can’t provide the complete picture. In addition to anatomical remains, paleontologists often focus on other biological samples such as coprolites, also called fossilized dung. But because of their composition, most coprolites are only preserved in aquatic environments like oceans and lakes, meaning it’s easier to reconstruct the menus of marine life than the food webs of land-based dinosaurs.
That’s partly why a team from the Natural History Museum at Berlin’s Humboldt University and the French National Center for Scientific Research initially suspected that their fossil in question (known as MNG 17001) was a coprolite. However, further analysis and morphological clues proved otherwise. Fossilized droppings are usually preserved in relatively regular cylindrical or conical shapes, with all residual bones suspended in an organic sedimentary matrix. This mineralized envelope is also generally rich in phosphorus, a consequence of the bacterial digestion of bones.
But MNG 17001 looks nothing like coprolite. The bone fragments are not housed in a sedimentary matrix and have very low levels of phosphorus. Overall, the team knew they were looking at regurgitation, or fossilized vomit, likely preserved due to the Bromacker site’s origins as a wet floodplain.
An ancient survival tip
Carnivorous dinosaurs are far from the only animals to regurgitate after a hearty meal. Even today, many predators frequently vomit more difficult-to-digest material like teeth, bones, and hair in order to conserve their overall energy. But MNG 17001 marks the first confirmed case of regurgitation from an entirely terrestrial Paleozoic predator.
Although paleontologists aren’t entirely sure who created the vomit, they have narrowed down the possibilities. CT scans allowed them to reconstruct the fossil’s dozens of half-digested bones in 3D, which they then compared to known species. These included the almost complete maxilla (upper jaw) of a small ancestor of today’s reptiles, Thuringothyris mahlendorffaeas well as the humerus belonging to the oldest known bipedal vertebrate, the bolosaurid Eudibamus cursoris. The final proof: a bone from a diadectide– proved the most revealing. The members of the Diadectidae were the first fully herbivorous tetrapods, as well as the first truly large land animals. Diadectsfor example, easily grew to a size of 10 feet long.
Potential suspects
Paleontologists are unsure of specific details diadectid species, but they know that whatever feasted on it had to be the same size. In the Bromacker region, only two predators do the job. The first suitor, Tambacarnifex unguifalcatusis not well known and probably resembles a huge monitor lizard. The second, Dimetrodon teutonisis much more recognizable with its distinct fin along its back.
Whatever its true identity, the ancient predator’s stomach ache provided a remarkable time capsule of Paleozoic life, death and regurgitation. The first fossilized vomit of its kind also hints at opportunistic hunting behaviors among the highest terrestrial predators and illustrates how carnivores have long relied on (admittedly unseemly) digestive trickery to maximize their chances of survival.
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