This Is the First Extinct Species Ever Found in Fossilized Barf—and It’s a Pterosaur

Around 110 million years ago, an apparent dinosaur ate two pterosaurs and four fish and, for whatever reason, threw them back up. A rare mix of geological conditions preserved this dinosaur vomit for human researchers to dig up—only for said researchers to catalogue it as a blob of fish remains, nothing special.

It wasn’t until Aline Ghilardi, a paleontologist at the Federal University of Rio Grande do Norte in Brazil, and her colleagues took a closer look that they realized the fossil was too strange and detailed to be just fish. Their suspicions were correct. The fossil contains the remains of an entirely new pterosaur—the first extinct species to ever be discovered inside, well, fossilized vomit.

The pterosaur, named Bakiribu waridza, had a “distinctive combination of jaw and tooth features not present in any known pterosaur,†Ghilardi, the senior author of a recent Scientific Reports paper describing the findings, told Gizmodo in an email. This was also the first time that a Ctenochasmatid, a rare filter-feeding pterosaur group, was discovered in Brazil or in rocks from this era, she added.

How vomit becomes fossilized

Bromalites—fossilized digestive remains such as coprolites (poop) and regurgitates (vomit)—are very rare but do exist. However, very specific conditions are required for regurgitates to survive for hundreds of millions of years, according to Ghilardi. First, the vomit has to be very rapidly buried in a calm, low-energy environment, and the mucus binding the material together needs to hold up over time

“Otherwise, they are destroyed by rain, waves, wind, or scavengers, or simply fall apart,†she said. The material inside is often partially processed or fragmented, meaning paleontologists often need to conduct a thorough microscopic examination of the remains.

Picking apart the “fishâ€

In this case, however, the remains of the pterosaur were surprisingly clear and identifiable; Ghilardi and colleagues were able to almost immediately flag what strongly resembled the “very peculiar teeth of Ctenochasmatid pterosaurs,†she recalled.

However, given the rarity of these pterosaurs, the team was hesitant to call this a new discovery. In fact, they didn’t even realize that the fossil itself was a regurgitate, although they did notice that the style and arrangement of the bones were highly unusual.

After a few rounds of sanity checks that involved cross-referencing the photos with other colleagues, the team decided to investigate the fossil in more detail. They considered various candidates for what the fossil could be, but the “pieces began to fall into place†once they considered that this could be a regurgitate containing pterosaur bones, Ghilardi said, adding, “What surprised me most was how an apparently unremarkable specimen turned out to contain something completely unexpected.â€

The unusually clean preservation of the bones also enabled the team to paint a detailed picture of what Bakiribu waridza could have looked like: elongated jaws densely populated with long, slender teeth, shedding “new light on the evolutionary trajectory of filter-feeding pterosaurs,†according to the paper. These pterosaurs would have captured food somewhat like modern flamingos. As for whose vomit this was, the researchers are not sure yet.

At the same time, this represents yet another paleontological “rediscovery†in which modern methods have uncovered new information about a previously excavated fossil. The new pterosaur, for example, sat for decades at the Museu Câmara Cascudo in northeastern Brazil until Ghilardi’s team more or less happened to catch its unique structure.

“Moments like this remind us why paleontology feels so magical,†Ghilardi said. “Extraordinary discoveries can be hiding quietly in a museum drawer, waiting for the right moment to reveal themselves.â€