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Listen, the dinosaurs are the best. We can have fun on the raptors, roar on the last T. Rex discoveries, and swoon on the feathers of Anchiornis . And we will cherish forever the titans, with their necks and their tails extended and imposing; brontosaurus, titanosaurus, and the rest of the sauropods.
While the Blue Whale remains the heavyweight champion, these sauropod giants were the greatest creatures to ever walk on earth. But they did not just grow one day. Their growth has been spread over a very long time and could have started much earlier than the researchers thought.
In an article published in Nature Ecology & Evolution this week, paleontologists analyzed the fossilized remains of two species. dinosaur who lived in a corner of the supercontinent Pangea between 237 million and 201 million years ago. It's been nearly 30 million years before the giants you read in science classes are on the scene.
Fossils show that instead of appearing in the Jurassic, the features that defined sauropods appeared earlier. for these giants to grow. Some of these traits, such as a bird-like respiratory system, would be used by similar dinosaurs 30 million years later.
"This system is related to the development of air sacs in their bodies – like modern birds – that allow them to have large reserves of oxygenated air, also helped them keep their bodies fresh despite its large size" , says the author of the study, Cecilia Apaldetti. "In addition, this type of breathing involved the presence of cavities (deep holes) in their bones – pneumatic skeleton – which lightened the weight and lightened it. would have favored to acquire a large body size. "
Cecilia Apaldetti is a researcher at the Museo de Ciencias Naturales, Universidad Nacional de San Juan, Argentina, who has been involved as a postdoctoral researcher and started studying a species ( Lessemsaurus ) already described in the scientific literature, but whose bones were twice as large as expected.
Then, in 2015, she and her colleagues came across a skeleton e partial of a species that had not been described before. "This new dinosaur is changing our understanding of how dinosaurs have become giants," says Apaldetti in an e-mail. "We did not expect a big dinosaur in the Triassic because we know that at that time the dinosaurs were usually small, no more than 3 tons, but this skeleton was more than that."
Apaldetti said that until now, it was believed that sauropods had evolved in the Jurassic, about 180 million years ago. "However, with this discovery, we can see that the first steps toward gigantism took place during the Triassic," says Apaldetti – many millions of years before these iconic, long – necked creatures are spreading around the world.
accumulated over the ages from the bones, but when they were left with a brand-new species, Ingentia prima who, with Antetonitrus an African dino South, and Lessemsaurus -was some unique features. They had vertebrae with air spaces (pneumatic vertebrae – a feature that returned to their successors) and accelerated growth, where they grew rapidly each year, accumulating signs of thrusts in their bones like rings in a tree .
"Typically in dinosaurs, this type of plexiform bone" squiggly "is only seen in very young individuals who are developing rapidly.As dinosaurs grow, their growth rate slows down and the texture of the Bone is more linear and organized.The histology of lessemsaurid shows that even though they had an annual slowdown in growth (presumably in winter), they still gained in size quickly in good seasons year after year, "Elizabeth Freedman Fowler, paleontologist who was not" The sauropods are of course the champions of size, and this study shows how the first sauropods have reached larger sizes than expected , growing very fast and keeping this high growth rate year after year. If you want to grow up, you can grow very fast, or you can grow slowly for many years, or a combination of both. Most dinosaur groups are turning to the "grow fast and die young" strategy, says Fowler.
The tendency to gigantism may have developed over these millions of years, it is a way for vegetarians like these sauropods. to stay safe in a hard world.
"Gigantism is an evolutionary survival strategy, especially for herbivorous animals, because pruning is a form of defense against predators, like any other [herbivore] it ran the risk of being slaughtered!" At the time, Apaldetti notes, there were massive carnivores associated with crocodiles – only much larger – occupying the same area as these dinosaurs.Biggering might have encouraged these carnivores to go after their prey more their own size.And this trait has continued to be advantageous for years
There are still many questions about the evolution of dinosaurs, but that adds a great deal of information to our understanding of the how the giants have come wandering the Earth … we still have a lot to learn about the growth rate strategies of the different dinosaur groups.If there is a rule about dinosaurs es, it's that there's always something to do to surprise us, "says Fowler.
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