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An analysis of the dinosaur diversity statistical models shows that they were not in decline when they were extinguished by an asteroid hit 66 million years ago.
Researchers from the University of Bath and the Museum of Natural History say that if the impact had not taken place, the dinosaurs could have continued to dominate the Earth.
Dinosaurs were widespread around the world at the time of the asteroid impact in the late Upper Cretaceous, occupied all continents of the planet, and were the dominant animal form in most terrestrial ecosystems.
However, it is still controversial among paleobiologists whether dinosaur diversity was in decline at the time of their extinction.
To answer this question, the research team put together a number of different dinosaur family trees and used statistical models to assess whether each of the major dinosaur groups could still produce new species today.
Their study, published in the Royal Society Open Science journal, found that dinosaurs were not in decline before the asteroid impact, which contradicts some previous studies. The authors also suggest that if the impact had not occurred, dinosaurs could have continued to be the dominant group of land animals on the planet.
The study’s first author, PhD candidate Joe Bonsor, said in a statement, “Previous studies by others have used various methods to conclude that dinosaurs would still go extinct because they were in decline towards the end of the Cretaceous period.
‘However, we show that if you expand the dataset to include newer dinosaur family trees and a larger set of dinosaur types, the results don’t point to that conclusion; in fact, only half of them do.’ .
It is difficult to assess the diversity of dinosaurs due to gaps in the fossil record. This may be due to factors such as which bones are stored as fossils, how much fossils have access to the rock to allow for excavation, and where paleontologists look for them.
Researchers used statistical methods to overcome these sampling biases by looking at speciation rates of dinosaur families rather than just counting the number of species in the family.
Joe Bonsor said: “The main point of our article is that it’s not as simple as looking at some trees and making a decision – the inevitable big bias in the fossil record and lack of data can often show a decline. cash, but this may not reflect the reality of the moment.
“Our data currently do not show that they were in decline, in fact some groups such as hadrosaurs and ceratopsians thrived and there is no evidence to suggest that they would have become extinct 66 million years ago if the extinction event had not taken place. “
While mammals existed at the time of the asteroid impact, it was only thanks to the extinction of the dinosaurs that they cleaned out the niches, allowing the mammals to fill them and thus take over the planet.
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