Dinosaurs¹ were already in an evolutionary³ decline tens of millions of years before the meteorite⁴ impact that finally finished them off, new research has found. The findings provide a revolution in the understanding of dinosaur² evolution. Palaeontologists previously⁵ thought that dinosaurs were flourishing right up until they were wiped out by a massive meteorite impact 66 million years ago. By using a sophisticated statistical⁶ analysis in conjunction with information from the fossil record, researchers at the Universities of Reading, UK and Bristol, UK showed that dinosaur species were going extinct at a faster pace than new ones were emerging from 50 million years before the meteorite hit. 

 

he analyses demonstrate that while the decline in species numbers over time was effectively ubiquitous among all dinosaur groups, their patterns of species loss were different. For instance, the long-necked giant sauropod dinosaurs were in the fastest decline, whereas theropods, the group of dinosaurs that include the iconic Tyrannosaurus rex, were in a more gradual decline.

 

Dr Manabu Sakamoto, University of Reading, the palaeontologist who led the research, said: "We were not expecting this result. While the asteroid⁷ impact is still the prime candidate for the dinosaurs' final disappearance⁸, it is clear that they were already past their prime in an evolutionary sense."

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