It seems that the Chicxulub asteroid that smashed into our planet 66 million years ago is killing all dinosaurs except the bird species has also changed the evolution of the shark forever.
According to a recent study, today's sharks owe their incredibly rich variety to a mass extinction event at the end of the Cretaceous.  […] Cell Biology The researchers investigated hundreds of fossilized teeth that could grow into two large sharks. Lines belonged, and discovered that the rulers of the Cretaceous oceans are practically extinct today.
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Also known as mackerel sharks, lamiforms are in the Today's oceans barely exist where they were outnumbered by Carcharhiniformes – one of the most diverse existing shark groups.
"Our study found that the shift from lamniform to carchariniform-dominated assemblages may be the result of mass extinctions of the Cretaceous," said study leader Mohamad Bazzi, paleontologist at Uppsala University in Sweden.
The same mass extinction event that sharks' future triggered off critical changes in mammalian evolution by lighting the light for the predominantly nocturnal mammals of the time and introducing them to a new dawn Inquisitr previously reported
"the shift from lami- to carbarhiniform-dominated assemblages may well have been the result of the Cretaceous mass extinction
The end-chalk extinction unleashed the modern shark diver sity https: // t. co / khbQvb5wHt about @UU_University @EurkAlert pic.twitter.com/Pk2NnKQXUj
– Michael Petter (@MikPetter) August 3rd, 2018
The team came to their conclusion after analyzing 597 dental fossils that were between 72 million and 56 million years old and belonged to ancient sharks from around the world, Gizmodo fossil Facing the challenge, fossil shark teeth are easier to find, notes Bazzi.
"Unlike other vertebrates, the cartilaginous shark skeletons are not easily discolored and our knowledge of these fish is largely limited to thousands of isolated teeth that have been lost throughout their lives," he says.
But teeth fossils are more than enough to reveal many important aspects of shark biology, including details about their diet, says Bazzi. All of these valuable details could help researchers figure out why some species of sharks are dying out, while others survive and how the endangered species can be prevented from extinction. More than 50 percent of shark species worldwide are currently either endangered, threatened or nearly threatened, the researchers show.
Co-author Nicolás Campione, Paleontologist at the University of New England in Armidale, Australia, also agreed
"By examining their teeth, we can gain insight into the lives of extinct sharks, and through understanding the mechanisms "Having shaped their development in the past, we may be able to provide some insights on how to mitigate further losses in current ecosystems."
After reviewing the shapes and sizes of the fossils, the team discovered that Lamniformes Extinct with broad, triangular teeth. In the meantime, the Carcharhiniforms flourished with exactly the same tooth type and evolved into a booming evolution that spawned more than 200 species.
The Carcharhiniformes that roam the oceans today are hammerhead sharks, tiger sharks, and blacktip reef sharks. The modern descendants of the prehistoric Lamniformes include the Great White Shark and the Makohai.
"Carcharhiniforms are the most common Haigroup today, and it seems that the first steps towards domination began about 66 million years ago," says Bazzi.
One possible explanation for this is the availability of food. The study shows that the Chicxulub asteroid killed a large number of marine reptiles and cephalopods, including those fed by the Lamniformes.
This freed the oceans for small, bony fish species, which increased the targeted prey of the Carchariniform sharks and also after the mass extinction and the end of the Cretaceous period. Therefore, it is quite possible that Carcharhiniforms might have survived this mass extinction because their prey also got through,
"It is likely that the loss of apex predators (such as lamiforms and marine reptiles) was favored over the medium term – trophic sharks, a role that meet many carcharhiniformes, "says a news release from Uppsala University.