Dinosaurs might have died out rapidly
London, January 20 (ANI): An analysis of fossils that were recently found in the Arctic suggests that the dinosaurs might have died out quickly, contrasting the idea that the massive reptiles declined slowly.
The study also suggests that the rapid extinction of dinosaurs might have resulted from an event like a massive meteor hitting Earth.
The finding contravenes the idea that dinosaurs were already declining by this time.
While geological evidence indicates that an impact occurred near the Yucatan Peninsula at the end of the Cretaceous 66 million years ago, it has still continued to be a matter of debate whether the event created an all-out apocalypse that wiped out the dinosaurs.
Even though many species died out, many others survived, including mammals and the small-feathered dinosaurs that were the ancestors of present-day birds.
Some palaeontologists are of the opinion that non-avian dinosaurs were in decline before the impact - perhaps as a result of major volcanic events or global cooling.
However, Pascal Godefroit and his colleagues at the Royal Belgian Institute of Natural Sciences insist that they have analysed fossils found in northeastern Russia, and found that dinosaurs were not in decline at all.
Reporting their study in Naturwissenschaften, the researchers say that no doubt dinosaur fossils have already been found in the Arctic, but the new find is unique because of its age.
Godefroit's team have dated the beds at between 68 million and 65 million years old, just before the time of the extinction.
"We found that there is no indication that the biodiversity of dinosaurs decreased just before the (extinction) event," Nature magazine quoted Godefroit as saying.
The researchers discovered that herbivorous, duck-billed hadrosaurs and velociraptor-like bipedal theropods seemed to be as common as they were in other parts of the planet at the time.
They even say that the presence of dinosaur eggshells found in polar regions also goes to show that the massive reptiles were residents rather than migrants.
However, palaeontologists are still proceeding with caution about the suggestion that the dinosaurs were not declining at the time.
"The presence of these dinosaurs is certainly concordant with the idea of a sudden extinction, but not incontrovertible evidence for it," says Tom Rich of Museum Victoria in Melbourne, Australia.
Robert Spicer of the Open University's Earth sciences department in Milton Keynes, UK, suggests that when the dinosaurs died out, the site might have lain along the edge of the Arctic Circle rather than deep within it.
"The weak link here is the palaeoposition of the site. With that said, such diversity even at this latitude suggests that dinosaurs were far more robust than we give them credit for. It makes me ask very serious questions about what could make animals that were resilient enough to live under these conditions suddenly go extinct," he said.
Bill Clemens of the University of California, Berkeley, believes that attributing the extinction of dinosaurs to any one cause would not be right, for some other stuties have suggested that their decline involved a variety of factors ranging from the introduction of predators to disease and habitat loss.
"Ask what is endangering modern amphibians, the answer varies according to species. I think the same was probably true with the dinosaurs," he said. (ANI)
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