The long shark is a car that once raged in the ocean

US scientists found a shark as big as a sharp-toothed car that once lived popularly along the Atlantic and Pacific coasts 20 million years ago.

The team found five 4.5 cm long teeth of extinct sharks in Japan, Peru and the United States (California and North Carolina), according to Live Science. The findings were published on October 3 in Historical Biology.

"The fact that a large shark of such a large geographic distribution indicates that we still know very little about the ancient marine ecosystem of the Earth" , Kenshu Shimada, paleontologist at DePaul University in Chicago, USA, the main author of research and sharing.

Megalolamna paradoxodon sharks live 20 million years ago.(Artwork: Wikimedia Commons).

The researchers named the shark that lived in the Middle East as Megalolamna paradoxodon , based on large-sized teeth very similar to the shark teeth of the Lamna family.

"At first glance, the teeth of Megalolamna paradoxodon look like giant teeth of Lamn a, including the modern shark and sharks. However, these fossil teeth are too big for Lamna family, As a reminder of the characteristics of their teeth, Otodus , we determined that this is a new species of the Otodontidae family and not directly related to the Lamna family , " Shimada said.

According to Shimada, M. paradoxodon has the teeth used for grabbing in the front of the mouth, and the teeth used for biting tear in the back, helping the animals eat their prey. Most likely they live in shallow coastal waters in the central latitudes, where the team found fossil teeth. Although they can only dig a tooth specimen, they can still estimate the length of this shark species by comparing it with that of a modern shark.

Fossil teeth of Megalolamna paradoxodon are found in many parts of the world.(Photo: Kenshu Shimada).

By analyzing the ratio of teeth to the body in modern relatives of M. paradoxodon, including sand sharks, mako sharks and great white sharks, the team estimates it can be as long as 3.7m. , equivalent to a car.

However, finding the exact size of M. paradoxodon is not easy, according to John-Paul Hodnett, expert on sharks and graduate students in biology at Saint Joseph's University in Philadelphia, who is not involved in the study. . Some modern sharks have small teeth but can be longer than 12m.

Prehistoric teeth also help researchers discover M. paradoxodon with relatives close to Carcharocles megalodon , the largest shark that once lived on Earth. C.megalodon is 18m long and has a stronger bite force than the tyrant dinosaur. Both shark species belong to the extinct Otodontidae family .