The spread of dinosaurs was perhaps favored by huge climate changes

A possible moment during the Carnian Pluvial Episode (Image courtesy Davide Bonadonna. All rights reserved)
A possible moment during the Carnian Pluvial Episode (Image courtesy Davide Bonadonna. All rights reserved)

An article published in the journal “Nature Communications” describes a research on the link between the dinosaur diversification that took place at the end of the Triassic period and an event known as the Carnian Pluvial Episode, which occurred around 232-234 million years ago. According to a team of researchers, in the middle of that period of climate change, dinosaurs started thriving, evolving into many different species, also taking advantage of the extinction of other animals.

There are many studies on the extinction of dinosaurs, which occurred about 66 million years ago. An increasing amount of evidence indicated as primary cause the impact of a huge meteorite and now the discussions concern the evaluation of its consequences including the possible trigger of a strong volcanic activity. However, around the origins of the dinosaurs there are more doubts because the reconstruction of that period is still incomplete.

Now a team formed by Massimo Bernardi and Fabio Massimo Petti of the Museum of Science, Trento, Italy, Piero Gianolla of the University of Ferrara, Italy, Paolo Mietto of the University of Padua, Italy, and Micheal J. Benton of the British University of Bristol tried to offer some new certainties about the period that led to the rise of dinosaurs.

We know that dinosaurs appeared at the beginning of the Triassic period, some 245 million years ago, after the greatest extinction in the history of life on Earth at the end of the Permian period. What wasn’t clarified yet is why they were rare for several million years and then quickly diversified within a few million years, a key event to make them the dominant group on the entire planet.

The researchers went looking for clues on the Dolomites, in Italy, where there’s the best known documentation of the Carnian Pluvial Episode (or Carnian Pluvial Event). At that time the arid climate changed considerably and relatively quickly with the emergence of much more humid conditions, including a large increase in rainfall, and then became dry again after a couple of million years.

In the Dolomites there are geological and biological evidence concerning dinosaurs. The fossil dating showing a rapid diversification of the dinosaurs matches an increase in carbon dioxide whose traces are present in the rocks. It’s a global phenomenon because the many traces found in the Dolomites correspond to those found also, albeit in smaller amounts, in Argentina and Brazil.

According to the reconstructions made in previous research, a strong volcanic activity in today’s western Canada caused a global warming and even acid rain. The strong climatic changes led to the Carnian Pluvial Episode. It’s possible that this wasn’t a great advantage for the early dinosaurs, rather a disaster for many competing species, which became extinct.

Other groups of animals such as lizards, crocodiles, turtles and mammals also took advantage of ecosystems left to them by that extinction. Dinosaurs were the ones that took the most advantage, starting a domain that continued for a whole geological era.

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