Giant reptiles used to be the food of ancient sharks

The new study says that about 85 million years ago, in the shallow waters of the ocean, a large group of white sharks vied for a giant reptile of the ancient plesiosaur.

In the battle for food, it seems that some shark teeth have broken and plugged into the bone of the plesiosaur. All of these artifacts were found by a Japanese high school student in 1968. Many fossils of other shark teeth were also discovered near the bones. Until recently, new paleontologists conducted surveys and described in detail these fossils in a scientific way.

The survey results reveal information about the source of ancient sharks, details will be published in the upcoming Journal of Vertebrate Paleontology. And although researchers believe that the reptile was dead, it was also possible that the sharks had attacked an injured Futabasaurus suzukii that was still alive.

Sketch an image of an ancient marine reptile named after the plesiosaur in Antarctica. The plesiosaur is described in the upcoming Journal of Vertebrate Paleontology with 4 very long fins and very long necks. (Photo: Nicolle Rager, US National Science Foundation)

Kenshu Shimada, a scientist from DePaul University, Chicago, and a Sternberg Historical Museum officer in Hays, Kansas, said: 'I don't rule out the possibility of an attack on a live animal because of them. I don't know how the prey died. It is also possible that the plesiosaur is sick or injured, and the sharks have a chance to kill it. '

Suzukii group

F. suzukii is a long-necked plesiosaur group, with four fins like push paddles swimming in ocean water. They live in the Jurassic and Cretaceous period. Shimada estimates that this group of creatures is about 7 meters long from the nose to the tail.

Shimada and her colleagues have come up with a reasonable hypothesis from looking at the fossil evidence and the lifestyle of sharks today.

The fossil record is made up of 87 shark teeth, of which 5 are found in the bones of the plesiosaur. All of these teeth belong to the shark species called Cretalamna appendiculata whose elongated shape looks like a white though slightly smaller. (Adult C. appendiculata species can reach a length of 2 - 4 m, while giant white sharks reach 7m long). Prior to this study, scientists speculated that this shark often feasted on attacking small fish with their sharp, sharp teeth.

'Maybe the fish used to be an ancient shark's food,' Shimada said. 'But at least, these fossils show that plesiosaur is also a food.'

Shark teeth in this survey were from at least 6 to 7 different C. appendiculata, of which several were mature and some were small.

What happened to shark teeth?

If the "meat" of these plesiosaurs occurs on the surface water, then the bones must have been washed up everywhere. But it seems that reality doesn't happen that way.

'The skeleton is still very intact. That makes me think that the time between the prey and the time it was buried in the sediment is relatively short, at most only a few months, ' Shimada said.

Shimada added: 'With fossil teeth obtained from many different sharks, it seems this is a collective attack.'

According to the Journal of Vertebrate Paleontology, about 85 million years ago, a group of sharks lost some of their teeth in a wreck of an ancient reptile. More than 80 shark teeth are found with reptile bone fossils. (Photo: Kenshu Shimada.)

He guessed that the shark teeth had been inserted to carve out the plesiosaur, and some shakes were trapped in the soft tissues of the prey. These tissues break down over time, leaving shark teeth scattered along the skeleton.

After this survey, Shimada hopes to have the opportunity to gather more evidence of nutritional relationships - which species of carnivores - of the Cretaceous period.'One of my goals is to try to reproduce the food web in the ocean at the time of the dinosaurs.'

Research results were presented last week during the annual meeting of the Vertebrate Paleontology Society in Bristol.