150-million-year-old vomit found in Utah offers ‘rare glimpse’ into prehistoric ecosystems

An artist rendering of a bowfin fish attempting to sneak up on a frog floating at the surface of a pond while another bowfin regurgitates part of a recent meal of frogs and a salamander. The bowfin fish is the suspected predator of a 150 million-year-old vomit fossil discovered in southeast Utah.
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Artist’s rendering of a bowfin fish trying to sneak up on a frog floating on the surface of a pond while another bowfin regurgitates part of a recent meal of frogs and a salamander. The bowfin fish is the suspected predator of a 150-million-year-old vomit fossil discovered in southeastern Utah. (Brian Engh via Utah State Parks Division)

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VERNAL — A recently discovered fossil in southeastern Utah appears to show the type of prey that predators fed on in the age of the dinosaurs and when the region was not as barren as it is today.

Utah paleontologists discovered a pile of amphibian bones that they say appear to have been spewed out by some sort of predator. This prehistoric vomit is believed to be 150 million years old, according to paleontologists with the Utah Geological Survey, Utah State Parks Division and the Flying Heritage & Combat Armor Museum in Washington.

His findings were published in Palaios magazine last month.

“This fossil gives us a rare glimpse into animal interactions in ancient ecosystems,” John Foster, curator of Utah’s Field House State Park Museum of Natural History and one of the study’s co-authors, said in a statement Tuesday. .

The team discovered the fossil while exploring the Morrison Formation, a famous paleontological site known for its fossils from the late Jurassic era, which ranges from about 148 million years ago to 155 million years ago. It’s mostly known for its dinosaur bones, but it’s also where scientists have found all sorts of other animals, including fish, salamanders, and frogs.

The southeastern Utah section of the formation features primarily prehistoric plants such as ginkgos, ferns, and conifers; however, paleontologists have also found amphibians and bow-finned fish there. These discoveries are why they believe the region was once home to a pond or small lake.

But during a recent survey, the team discovered an oddly arranged fossil. It was a group of bones that included “elements” of at least one small frog or tadpole and would be the “smallest salamander specimen reported from the formation,” the researchers wrote in the study. Some of these bones were only 0.12 inches long, which are among the smallest set of bones within the formation.

They added that the chemical and bone structure of the fossil indicates that it is a regurgitalite, which is a fossilized form of vomit. The team noted that it is the first such find within the Morrison Formation and also within the Jurassic period of North America.

What remains unclear 150 million years later is what killed the species within the regurgitalite. Foster notes that previous research places bowfin fish in the region at that time, which he sees as the “best current match” for the predator behind the fossil. Scientists have discovered species of fish, salamanders, and frogs in the Morrison Formation for more than a century.

“While we can’t rule out other predators, a bowfin is our current suspect, so to speak,” he said, explaining that fish – and other animals – sometimes regurgitate their recent meals when they are being chased or want to distract a potential predator. predator.

“There were three animals that we still have today, interacting in ways that are also known today between those animals: prey being eaten by predators, and predators perhaps being pursued by other predators,” he added. “That in itself shows how similar some ancient ecosystems were to places on Earth today.”

The find is the team’s latest in the region. Two of the three study co-authors also help discovers a massive 151-million-year-old water bugwhich led to an article being published in 2020.

James Kirkland, the state paleontologist who co-authored both studies, said paleontologists plan to continue searching the site where the prehistoric vomit was discovered to see if they can find more evidence of the region’s past ecosystem.

“I was so excited to have found this site, as Late Jurassic plant localities are so rare,” he said in a statement. “Now we must carefully dissect the site for more little wonders among the foliage.”


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Carter Williams is an award-winning reporter covering general news, outdoors, history, and sports for He previously worked for the Deseret News. He is a transplant from Utah by way of Rochester, New York.

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