A man exchanges a 360 million year -old shark jaw for a few beers<

This jaw was brought back by a group of Dutch amateur paleontologists after a fossil hunt in the Ardennes, as they used to do between 1980 and 2001.The maxilla was then offered to the Institute in 2016.The bone had itself been sold to the Dutch by a career worker Thomas in Comblain-au-Pont, in the province of Liège, against some beers.Although we already know that sharks have formerly swam in our regions, it is an exceptional discovery because of its rarity.Indeed, this cartilage from a species of prehistoric sharks, called ctenacanthidae and whose length could reach 2.5 meters, is particularly well preserved within a rock.However, the raw sediments in which the fossil was found, mainly arkose (a type of sandstone), are generally not very conducive to the fossilization of the cartilages.The analysis of these sediments, which date back to a period when the Ardennes massif was still a deep sea, allowed the research team to date the fossil.

This jaw is thus the oldest shark fossil in Europe.Similar discoveries had only been made in the United States and Australia.Dorsal teeth and thorns are the most often found sharks.

Another phenomenon that explains the scarcity of such a discovery: the organization of the food chain at the time when these specimens lived.According to scientists, it seems that sharks were playing in a hostile environment and were appreciated prey of predatory and placoderms (equipped with a sort of shell) which could reach eight meters long.""""This is probably one of the reasons why we find so few shark fossils in good condition.Many shark bodies could not fossilize because their population was low and many of them ended up being eaten by predators.The shark population was constantly under pressure, """"said Sébastien Olive, paleontologist at the Royal Institute of Natural Sciences.""""Their true evolution and diversification only took place after the disappearance of their predators in the carboniferous age, 300 to 360 million years ago.""""

Thanks to a 3D analysis of the rock in which the jaw is, scientists were able to determine the size of the specimen to which it belonged. """"L'exemplaire en question devait mesurer environ 1,80 mètre.We can determine this on the basis of the size of the lower jaw, which measures 22 centimeters long and 8.5 centimeters high.""""

These works were published in the American scientific journal Journal of Vertebrate Paleontology.