New research suggests that the mass extinction event that led to the rise of dinosaurs might have happened in the latter stages of the Triassic Period, at a time when dinosaurs were rare but already making their presence felt on our planet.
In a study published Monday in the journal Nature Communications, researchers at the University of Bristol in England discovered that dinosaurs might have become the dominant species on Earth after an event called the Carnian Pluvial Episode, which took place about 232 million years ago. As noted by UPI, the first dinosaurs are believed to have appeared around 245 million years ago, just as the Triassic Period was kicking off. But the new findings suggest that dinosaurs, which were still rare in the Early Triassic, only became common in the early parts of the Late Triassic, after the aforementioned extinction event.
“The discovery of the existence of a link between the first diversification of dinosaurs and a global mass extinction is important,” said study co-author Mike Benton, a professor at the University of Bristol.
“The extinction didn’t just clear the way for the age of the dinosaurs, but also for the origins of many modern groups, including lizards, crocodiles, turtles, and mammals – key land animals today.”
In order to come up with the new theory behind the rise of dinosaurs, the researchers analyzed ancient rock deposits in the Dolomites, a Northern Italian mountain range. According to Earth.com, the team found several dinosaur footprints in the area, which then allowed them to determine a starting point for the dinosaurs’ takeover as Earth’s most common species. After comparing the new findings against rock layers from Argentina and Brazil, the researchers concluded that dinosaurs also became commonplace in those countries around the same time, hinting that the species’ rise was concurrently happening in different parts of the world.
“We were excited to see that the footprints and skeletons told the same story,” said University of Bristol researcher and study lead author Massimo Bernardi.
“We had been studying the footprints in the Dolomites for some time, and it’s amazing how clear cut the change from ‘no dinosaurs’ to ‘all dinosaurs’ was.”
As further stated by UPI, the rise of the dinosaurs coincided with the end of the Carnian Pluvial Episode, which resulted in most of our planet’s species getting wiped out after volcanic eruptions in Western Canada drove chaotic periods of climate change. Earth.com described these changes as regular shifts from “dry conditions to humid and back to dry again.”
The research lends credence to earlier theories that there was another extinction event in the middle of the Permian and Cretaceous Periods that led to the rise of the dinosaurs. According to a 2014 article on The Conversation posted by University of Birmingham researcher Richard Butler, the episode at the end of the Permian allowed dinosaurs to have “environmental space” to evolve, while the extinction event that wrapped up the Cretaceous led to their demise. Like the University of Bristol team did in their new paper, Butler wrote that the Carnian Pluvial Episode, which he did not identify by name, took place at the end of the Triassic and “allowed dinosaurs to rise to dominance and evolve seemingly unfeasible body sizes.”