Washington: Researchers from Yale University have discovered the youngest dinosaur preserved in the fossil record before the catastrophic meteor impact 65 million years ago.
The finding indicates that dinosaurs did not go extinct prior to the impact and provides further evidence as to whether the impact was in fact the cause of their extinction.
Researchers discovered the fossilized horn of a ceratopsian – likely a Triceratops, which are common to the area – in the Hell Creek formation in Montana last year. They found that the fossil buried just five inches below the K-T boundary, the geological layer that marks the transition from the Cretaceous period to the Tertiary period at the time of the mass extinction that took place 65 million years ago.
Since the impact hypothesis for the demise of the dinosaurs was first proposed more than 30 years ago, many scientists have come to believe the meteor caused the mass extinction and wiped out the dinosaurs, but a sticking point has been an apparent lack of fossils buried within the 10 feet of rock below the K-T boundary. The seeming anomaly has come to be known as the "three-meter gap."
Until now, this gap has caused some paleontologists to question whether the non-avian dinosaurs of the era – which included Tyrannosaurus rex, Triceratops, Torosaurus and the duckbilled dinosaurs – gradually went extinct sometime before the meteor struck. (Avian dinosaurs survived the impact, and eventually gave rise to modern-day birds.)
"This discovery suggests the three-meter gap doesn``t exist," said Yale graduate student Tyler Lyson, director of the Marmarth Research Foundation and lead author of the study.
"The fact that this specimen was so close to the boundary indicates that at least some dinosaurs were doing fine right up until the impact,” added Lyson.
While the team can``t determine the exact age of the dinosaur, Lyson said it likely lived tens of thousands to just a few thousand years before the impact.
"This discovery provides some evidence that dinosaurs didn``t slowly die out before the meteor struck," he said.
The study has been published online in the journal Biology Letters.