The word fossil may conjure up the bones of a creature itself – tall T-Rex, small trilobite, medium sized giant sloth. But life can be immortalized in other, more perverse ways: in the traces that an organism leaves behind during the course of its life. Some archaeological excavations are semi-poetic. Dinosaur footprints or a burrow carved by an ancient worm begs the question: Who left this behind? Other archaeological excavations are less poetic but more mysterious. The presence of a small round lump or a small lump of bone raises not one but two questions: who left this behind, and from what end it appeared? In other words: tube or barf?
All fossils require some deciphering, but anything excreted or regurgitated by an animal millions of years ago can be a real mystery. The first type, called coprolites, is more common, and often looks exactly what you’d expect: brown lumps. But just as modern stool is a wonderful thing, ancient stool can take many forms. Some curly brown fossils that may look like an unmistakable tube are actually crooks, also called false. (The Wilkes Formation in southwest Washington is a precious collection of such false ruins, Inorganically formed When silt and mud fill up hollow shards of wood.)
More rare than coprolites regurgitation, or fossilized vomit. “It is rare to find direct evidence of who ate who, or who vomited who, in the fossil record,” said Brian Eng, paleontologist and film director. Although the soft barn of ancient herbivores would have less chance of geological immortality, predatory bulls might contain at least some bones, according to John Foster, curator of the Utah State Field House Museum of Natural History. .
Foster and colleagues describe a new hard fossil in a research paper recently published in the journal. Palios. The newly described regurgitalite is very small—about the length of a staple piece—but contains the scattered remains of at least two frogs and a sliver of salamander
When Foster’s team first dug into the rock, they didn’t think much of it. They were working at the famous Morrison Formation in Utah, a late Jurassic site containing hordes of dinosaur bones including sauropods. Diplodocus, whose cruciform phallus may not survive the ravages of time. But Foster and his colleagues focused on a lesser-known patch of Morrison whose abundance of fossilized plants gave it the nickname “Salad Bar. There is still a lot to be found in this formation, and some of it will be cold,” said Eng.
The researchers returned the specimen to the museum, where it lingered for a year among a variety of puzzles — “things we can’t pinpoint what,” Foster said. Some of these puzzles require two or three cycles under the microscope to become clear. For example, one of the Salad Bar puzzles turns out to be a file fossil water bugwhose venous wings initially looked like veins of paper.
Using a microscope, Foster realized that what he was looking at was not a plant at all, but a jumble of amphibian bones, some of which were only three millimeters long. And the bones did not come from a single amphibian tragically disassembled, but rather a loose pile of various amphibians. The frogs were very small – an inch or two long at most. “We knew we had at least two frogs,” Foster said. “We found at least one bone from a salamander.”
But then the real question came to the sample. Foster paused, “to see if the thing vomited or passed out, basically.”
There were some visual cues. “Most of the coprolites you find are basically little ovals or little tubes or something,” Foster said. “They retain a kind of three-dimensional character.” But the bone mixture was flat, without the typical landmass of coprolites, and the stone around it had many lamellas – deposits of sediment that probably accumulated each year around the small mound. But to be sure, the researchers had to perform a geochemical analysis. X-ray fluorescence scanning of the sample revealed that the sample did not contain elevated levels of phosphorous, which is generally indicative of coprolite. The only elevated phosphorous was found in the bones, which indicates that phosphorus was not removed from the fossil during the process of metamorphism into rock.
The sample contained several specks of a fuzzy gray mass, which also did not contain phosphorous. Foster hopes to survey the fossil with a more precise machine at the University of Utah, allowing him to focus on specific areas. “He’ll be able to give us a pretty good indication of what those unidentified substances are,” Foster said.
But if a fossil vomits, who vomits? Currently, the identity of the perpetrator has been lost over time. The researchers’ best guess is a fish, possibly similar to the modern puffin, because of the scales they found around the site. Other predators, such as turtles and semi-aquatic mammals, are likely as well, Foster said, but they haven’t been discovered near the site yet. Anything larger, like a prehistoric crocodile, wouldn’t bother on frogs the size of a lemon. “The pub gives us a window into what was going on in the ecosystem,” Eng said.
Engh, the ancient artist tasked with illustrating what a reggaeton might look like in real life, had a challenge ahead. He said that at first he was simply planning to show you how to eat fish. But then you’ll ask all the questions about, why is this fish being eaten? And it also wouldn’t show what the fish were eating.” For a precautionary answer to this question, Eng tried another diagram of a fish being gnawed by a crocodile and jumping in a defensive fashion—a way to distract a predator. But without evidence of crocodiles in this corner of the Morrison River, this has been cancelled. version also.
The last illustration is inspired by jaws Poster: Bowfin fish approaches the forgetful frog from below, ready to chomp. “I realized I still wanted to show off the glamour, so I added another puffin in the background,” Eng said. When Engh’s wife, an evolutionary biologist who studies fish, reported that lungfish chew by encasing everything they eat in a ball of mucus and emptying it completely, Engh added a sticky layer of mucus to his vomiting frog.
The bones within the shell were not highly fragmented, indicating that they may have been only partially digested by the predator. It’s possible that the predator may have gutted the frogs ingesting defensively or after digesting the frog meat in an attempt to cleanse the frog bones, Foster said. The mucus bubble, he added, would have helped the bones stick together and hold them together, possibly insulating the bones from scavengers or microbes.
Foster was astonished that the fragile pile of fine, mostly hollow bones had ever been preserved. But his favorite part of the fossil is how it captures the interactions of the modern-looking animals that happened to have lived 150 million years ago. “It kind of helps explain how not everything in the time of the dinosaurs was really weird and weird,” Foster said. “Some of them were very familiar to us.” If we were sitting on the banks of this Jurassic pond, said Foster, we might have heard a chorus of frogs, and perhaps even the distinct and immortal sound of a carnivore tossing a frog that no longer danced.