Researchers have identified what is believed to be the oldest known fossilised vomit ever discovered on land, providing an extraordinary glimpse into the diet and behaviour of prehistoric predators that lived nearly 294 million years ago.
The study centres on a compact cluster of fossilised bones unearthed in 2021 at the Bromacker fossil site in central Germany. Initially, scientists were unsure whether the remains represented regurgitated food, fossilised faeces or simply bones that had been naturally transported and compressed by geological processes.
The mystery was investigated by palaeontologists Arnaud Rebillard, a doctoral researcher at the National Museum of Natural History, and Jean-Sébastien Steyer of the French National Centre for Scientific Research.
Using X-ray fluorescence (XRF) analysis, the team examined the fossil’s chemical composition. The absence of elevated phosphorus levels, typically associated with fossilised faeces, ruled out the possibility that the specimen was a coprolite. Instead, the researchers concluded it was a regurgitalite – fossilised vomit preserved over hundreds of millions of years.
A subsequent three-dimensional scan revealed that the fossil contained the remains of three separate prey species consumed by a single predator. These included the small reptile Thuringothyris, the bipedal reptile Eudibamus and a large herbivorous Diadectid.
Identifying the predator proved more challenging. However, based on the known fauna from the Bromacker site, researchers believe only two large synapsids – Dimetrodon and Tambacarnifex – were large enough to have swallowed and later regurgitated all three animals, including the sizeable herbivore.
Although fossilised droppings and regurgitated remains are regularly recovered during excavations, they have historically received far less scientific attention than skeletal fossils. Early palaeontologists, including William Buckland and Mary Anning, recognised their potential, but many specimens have remained largely unstudied in museum collections.
Although fossilised droppings and regurgitated remains are often recovered during excavations, they have received far less attention than skeletal fossils in the past. Early palaeontologists like William Buckland and Mary Anning recognised their potential, but many specimens have been largely left in museum collections.
The scholars say digestive fossils provide unique evidence of ancient ecosystems. They can also tell us which species lived next to each other, as well as predator-prey relationships, feeding strategies and ecological interactions that skeletal remains cannot show.
In this case the fossil shows that the predator was an opportunistic hunter able to eat a wide variety of prey.
The Bromacker fossil site has been dated to about 294 million years ago, which puts it at the beginning of the Permian. During this time the terrestrial ecology was becoming more complex, the climate on Earth moving from humid tropical conditions to a more arid climate and setting the stage for the mass extinction that would eventually come to define the Permian.
As much as scientists believe that the ancient regurgitalite has many of its secrets hidden away, they say more research on related fossils could provide new insights into prehistoric food webs and the evolution of some of the world’s earliest complex land ecosystems.
Sources : CNRS
