This Historic Sea Cow Was Killed by a Croc and Eaten by a Shark

This Historic Sea Cow Was Killed by a Croc and Eaten by a Shark

By Meghan Bartels

The circle of life is gorgeous and ugly—generally so ugly that it makes the fossil document downright macabre, hundreds of thousands of years after the very fact.

That’s what occurred with an historical manateelike animal whose stays had been uncovered in western Venezuela in 2019. The specimen didn’t draw a lot curiosity at first; it isn’t significantly nicely preserved. However as scientists appeared nearer, they realized the creature’s cranium components and vertebrae had been riddled with chunk marks—from two very completely different mouths.

“As quickly as you begin to try the main points, you notice that there’s something actually particular concerning the animal,” says Aldo Benites-Palomino, a final-year Ph.D. scholar in paleontology on the College of Zurich. He’s a co-author of a paper printed on August 29 within the Journal of Vertebrate Paleontology that experiences the discover and makes use of the fossilized proof of violence to begin piecing collectively how species interacted on this little-studied area of South America.

On supporting science journalism

In the event you’re having fun with this text, take into account supporting our award-winning journalism by subscribing. By buying a subscription you’re serving to to make sure the way forward for impactful tales concerning the discoveries and concepts shaping our world in the present day.

“Chew marks are actually attention-grabbing to check since you don’t really feel like a paleontologist—you are feeling principally like a forensic specialist,” Benites-Palomino says. The case at hand:

Sufferer: one sea cow, genus Culebratherium—maybe 16 ft lengthy, though the fossil isn’t nicely sufficient preserved for the researchers to make certain.

Time of dying: early to mid-Miocene, 23 million to 11.6 million years in the past.

Scene of the crime: an historical shoreline of brackish water and mangrovelike forests.

Benites-Palomino and his colleagues started their investigation by figuring out three several types of chunk wounds on the fossilized bones. One kind of chunk mark left small, round indentations on the ocean cow bone. One other left deep, spherical pits with an incision arcing off them. And one more left slender, slitlike marks with triangular imprints.

After which there was what paleontologist Sally Walker of the College of Georgia, who was not concerned within the new analysis, calls a “smoking tooth”: a fossilized chomper discovered embedded within the fossil between the ocean cow’s neck and ribcage. The stray tooth, from an extinct tiger shark known as Galeocerdo aduncus, means that the slitlike marks had been left by the identical shark scavenging on the ocean cow’s stays, the research’s researchers say. This type of scavenging can also be possible why the skeleton is so fragmentary: messy eaters most likely tore off items of the carcass and carried them away. Walker says that she’d wish to see proof that shark enamel are unusual within the space to rule out a coincidental discover, nevertheless.

In the meantime Benites-Palomino and his colleagues attributed the primary two varieties of chunk marks to some type of crocodilian—though pointing the finger at a selected suspect species is hard, he says. That’s as a result of the world on the time was what he calls “a paradise for crocodilians” and since members of this order typically have equally sized enamel even when their physique measurement varies. “Until it’s one thing gigantic or one thing tiny, it’s actually tough” to pinpoint what species was doing the biting, Benites-Palomino says.

The researchers posit that the crocodilian first snapped on the sea cow’s snout—leaving the small round indentations—then snatched on the animal and used its tail to spiral its physique and tear on the animal in what scientists time period a “dying roll.”

The dying roll is a standard tactic amongst almost all fashionable crocodilians, says Stephanie Drumheller, a paleontologist on the College of Tennessee, Knoxville, who was not concerned within the new analysis. Though it’s a believable approach for an historical crocodilian to have used, she’s not satisfied the conduct ties to the curving chunk marks as tightly because the researchers recommend, nevertheless. “Positively lining up chunk marks with particularly the dying roll—I’m not comfy with that,” she says. “It’s not a pleasant, neat one-to-one.”

Ultimately, the staff’s story of what precisely occurred to the battered sea cow is only a speculation, Walker emphasizes, and one that will by no means be confirmed. However no matter precisely befell the unfortunate creature all these hundreds of thousands of years in the past, its destiny speaks to the complexity of its ecosystem and is a compelling reminder, all three scientists say, that historical meals webs had been simply as intricate as fashionable ones. “Chew marks give us this wonderful window into the meals webs in these extinct ecosystems,” Drumheller says.

And since the formation the ocean cow was present in has been little or no studied, there’s nonetheless so much to study this Venezuelan space’s distant previous, the scientists behind the brand new analysis say. It’s simply considered one of a number of compelling discoveries made in South America, says Benites-Palomino, who hails from Peru and works with colleagues from throughout the continent. “I’m in the midst of the beginning of this golden age of paleontology in South America,” he says. “We’re discovering various materials in each single nation.”