No matter how bad your day is going, think of the ancient manatee, the subject of a recently published study by an international team of researchers.
Dragged by a crocodile before its body was chewed up by a shark some 20 million years ago, it would not have been a pleasant end for the dugong. But an examination of its remains is giving modern experts fascinating insights into the marine food chain of the early to middle Miocene – which appears to have functioned in a similar way to today.
“Today, when we observe predators in the wild, we often find carcasses of prey animals, which prove their function as a source of food for other animals. However, fossil finds of these are rarer,” says paleontologist Aldo Benites-Palomino from the University of Zurich in Switzerland.
“We weren’t sure which animals could serve as a food source for multiple predators.”
The story begins with the discovery of some unusual stones by a local farmer south of the city of Coro in northern Venezuela. When researchers were called in, they found that the minerals contained parts of a skeletal fossil, including a section of a skull and 18 different vertebrae.
Analyses showed that they were left behind by an individual of the extinct genus of manatees. Culebratherium which had a most unfortunate ending.
An examination of the bite marks found on the fossils helped researchers reconstruct the fossil’s final hours. It appears that it was attacked by a crocodile, which tore the manatee apart and possibly knocked it to the ground in a death roll. The team also found marks on the skeleton that matched the shape and size of the teeth of an extinct tiger shark (Galeocerdo sp), who apparently ate meat from dead or dying animals. They even confirmed the shark species – G. aduncus – from the tooth it left in the manatee’s neck.
It seems that after the crocodile had eaten its fill, another carnivore came to peck at the leftovers.
By analyzing the deposits surrounding the area where the remains were discovered – far from any previous fossil finds in the region – researchers were able to date the fossil to be about 20 million years old.
“Our results are one of the few pieces of evidence that there were multiple predators and therefore a single prey, and thus provide insight into food chains in this region during the Miocene,” says Benites-Palomino.
The fact that such a comprehensive picture of the demise of this manatee was created is thanks to the hard work of the research team: in total, several months of work were needed to identify the fossil and find out what happened to it.
“Evidence for trophic interactions is not rare in the fossil record, but it is usually represented by fragmentary fossils that contain traces of ambiguous significance,” the researchers write. in their published paper.
“Distinguishing between tracks left by active predators and scavengers is therefore often a challenge.”
The study was published in Journal of Vertebrate Palaeontology.