Image: © lassedesignen/Stock.adobe.com
New analysis has refuted the claim that dinosaurs were in decline at the time of their extinction.
If an asteroid had not hit Earth 66m years ago, dinosaurs might have continued to dominate the planet, according to new research.
A team from the University of Bath and the UK National History Museum has published a study to Royal Society Open Science saying that, contrary to some scientific thinking, dinosaurs were not in a state of decline prior to the mass extinction event.
The team collected a set of different dinosaur family trees and used statistical modelling to assess if each of the main dinosaur groups was still able to produce new species at this time. Prior to the asteroid impact during the Late Cretaceous period, dinosaurs were globally widespread and were the dominant form of animal of most terrestrial ecosystems.
‘Isn’t as simple as looking at a few trees’
“Previous studies done by others have used various methods to draw the conclusion that dinosaurs would have died out anyway, as they were in decline towards the end of the Cretaceous period,” said first author of the study, Joe Bonsor.
“However, we show that if you expand the dataset to include more recent dinosaur family trees and a broader set of dinosaur types, the results don’t actually all point to this conclusion — in fact, only about half of them do.”
The statistical methods used by the team were designed to help overcome gaps in fossil records caused by a number of factors. This included which bones are preserved as fossils, how accessible they are, and the locations where palaeontologists search for them.
“The main point of our paper is that it isn’t as simple as looking at a few trees and making a decision,” Bonsor added.
“The large unavoidable biases in the fossil record and lack of data can often show a decline in species, but this may not be a reflection of the reality at the time. Our data don’t currently show they were in decline, in fact some groups such as hadrosaurs and ceratopsians were thriving and there’s no evidence to suggest they would have died out 66m years ago had the extinction event not happened.”
