Brandon U’s Dr. MacDougall Unveils the Oldest Known Fossil Vomit From a Land Predator
Dr. Mark MacDougall, an Assistant Professor of Biology at Brandon University and a paleontologist, contributed to a study that may chronicle the oldest fossilized vomit from a terrestrial predator, dating back nearly 290 million years. The international study, now published in Scientific Reports—an open-access, peer-reviewed journal that welcomes research across natural sciences, medicine, engineering, and beyond—adds a striking find to our understanding of ancient ecosystems.
The team documents a fossilized vomit, more precisely termed a regurgitalite, recovered from the Bromacker fossil site in Germany. The specimen consists of the preserved remains of a predator’s rejected meal, containing partially digested bones that were expelled rather than digested, marking the earliest confirmed instance from a fully land-based ecosystem.
In modern animals, including humans, this same reaction occurs when something ingested proves troublesome. Discovering evidence of this behavior so far back in time provides scientists a rare window into ancient feeding habits, food webs, and predator–prey relationships within one of the planet’s earliest terrestrial communities.
“This fossil is pivotal for understanding how early land ecosystems functioned,” MacDougall notes. “It’s uncommon to obtain such direct evidence of who was eating whom nearly 300 million years ago. In this case, the predator evidently bit off more than it could stomach.”
Employing CT scans and chemical analyses, the researchers identified bones from at least three different animals inside the regurgitated cluster: a small reptile, a swift, lizard-like creature, and a fragment from a much larger herbivore. All evidence points to a top predator—likely an early mammal relative akin to Dimetrodon—consuming a mixed meal and later regurgitating it.
MacDougall explains that the conclusion rests on the bones’ arrangement: “The way the bones are oriented is highly unusual. In a typical death scenario, you wouldn’t expect that kind of alignment. These bones are aligned as if they were inside a stomach. That pattern is a strong clue we’re looking at regurgitated material.”
Additional clues come from multiple animals found together in the sample, suggesting a diverse prey selection during that period. The team also used techniques to analyze the surrounding rock’s chemical makeup, revealing mineral and elemental signatures characteristic of vomit rather than ordinary sediment.
Taken together, these lines of evidence lead the researchers to interpret the find as likely fossil vomit.
Why Dimetrodon as the likely culprit?
MacDougall explains that only a limited number of sizable predators at the Bromacker site could have preyed on the assemblage in question. By matching the identified bones to their likely species and considering their sizes, the team narrows the candidates to a handful—including Dimetrodon-like creatures—that could have swallowed the observed mix of prey items.
Looking ahead: the oldest fossilized skin impressions
In a related effort, MacDougall co-authored a paper describing the oldest known fossilized impressions of scales. “Many ancient animals wore scales similar to modern lizards, and we found impressions in the rock showing the scale shapes and their likely placement on the body,” he says. Such skin impressions are rare because soft tissues often decay long before fossils form, making these discoveries especially valuable.
The researchers are continuing to study the Bromacker site, uncovering more fossils—from small reptiles and amphibians to potential mammal ancestors—expanding our picture of early life and the evolution of terrestrial ecosystems.
