An “extraordinary” pile of prehistoric puke discovered in southeastern Utah contained an insightful treasure for paleontologists: fossilized amphibian bones, likely vomited up by an ancient fish, according to a study published last month.
The discovery indicates that at least one ancient animal apparently puked up a meal to evade a predator — previously undocumented behavior from the North American Jurassic period.
“It’s pretty exciting,” state paleontologist James Kirkland said, noting that the discovery will “fill out a lot of information for what we think was going on in Utah during the upper-Jurassic [period].”
The ancient vomit was found by John Foster, museum curator at the Utah Field House of Natural History. Foster and Kirkland had been scouting sites east of Bears Ears National Monument in 2016 when they came upon what their survey notes describe as the “Jurassic Salad Bar” site.
The site is a trove of remarkably preserved fossils from the upper-Jurassic period, one of the finest ever discovered in the U.S. It’s located in the Morrison Formation — the same rock layer as the dinosaur remains discovered at Dinosaur National Monument.
At the “Salad Bar” site, researchers “literally could peel leaves of extinct plants right off the rock,” Kirkland said. They also found fossilized crayfish, giant water bugs and fish scales — and, the fossilized fish puke.
The retched remains weren’t immediately identified as vomit, Kirkland said, since the pile itself only measured about an inch across in the fossilized slabs he and Foster were examining. But when Foster analyzed the tiny bones he found under a microscope, he realized they belonged to two different types of animals — a juvenile tadpole and a salamander.
“Having them mixed, it became more likely this is from a frog-salamander eater,” Kirkland said. “Nothing else like that was found at this time — and it’s a real important, sensitive site, and we hope to get a lot more out of it, but this was the only thing like it we found. Pretty extraordinary.”
(Utah State Parks) During the Late Jurassic of what is now southeastern Utah, a bowfin fish attempts to sneak up on a frog floating at the surface of a pond, along with leaves of ginkgophytes, while another bowfin regurgitates part of a recent meal of frogs and a salamander. This is one possible scenario of the origin of the new fossil from the Morrison Formation. Artwork by Brian Engh.
The likely source of the vomit was an ancient bowfin fish, which may have regurgitated its most recent meal to distract a predator in pursuit 150 million years ago — when this area of southeastern Utah was a swampy marshland.
“This fossil gives us a rare glimpse into the interactions of the animals in ancient ecosystems,” Foster said in a news release this week. “There were three animals that we still have around today, interacting in ways also known today among those animals — prey eaten by predators, and predators perhaps chased by other predators.”
“That itself shows how similar some ancient ecosystems were to places on Earth today,” he said.
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