When a meteorite hit Earth 65 million years ago, destroying an era dinosaur This huge reptile was already in bad shape. For 10 million years, they’ve been in decline. This is the conclusion
a lesson, Published Tuesday in the magazine natural connection, Led by Fabian Condamine, a CNRS researcher at the Institute of Evolutionary Sciences at
Montpellier (Herault).
A particularly valuable find, for those interested in dinosaurs: Paleontologists are debating whether their extinction occurred suddenly, or if the 12 km2 meteorite was simply dealing with a “reversal of grace,” the researchers noted. Fabian Condamine tends to the second hypothesis.
lower temperature
“The decline will be due to significant environmental changes, including lower temperatures during the Cretaceous period,” he asserted. We’ll lose 7 degrees Celsius, at least. For these species, unable to generate their own body heat, and requiring high temperatures to feed, move or reproduce, this climate change is catastrophic. “This drop in temperature is associated with increased extinctions” of dinosaurs, continued Fabian Condamine.
Worse, the first extinctions were linked to herbivores, upsetting the balance of the ecosystem. In particular, the gradual extinction of evil carnivores, which found some herbivores to eat. Researchers at Montpellier explain: “If we draw an analogy with today, with the plains of Africa, for example, then all herbivores, giraffes, elephants, zebras, wildebeest, deer are very structural for the whole ecosystem. Because all predators depend on them. “But also parasites and plants. Without elephants, there is no longer the same vegetation.”
A “lesson” for people whose “environment is deteriorating”
To reach this finding, an international team led by Fabian Condamine analyzed the evolution during the Cretaceous period of six major dinosaur families, including the famous tyrannosaurs, triceratops and hadrosaurs. The researchers collected piles of data from fossils over several years, and estimated the evolution of each species over thousands of years.
For Fabian Condamine, the study highlights “a good example of an overly dominant group” dealing with gradually declining external distractions. “We can compare this with other dominant groups,” said the researcher. I think in particular certain groups of sharks, which are currently on the verge of extinction. And that man? “It’s a lesson for us too, that’s for sure,” he said. Our environment is getting worse. Especially in terms of climate. “
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