trying to To solve this heated debate, a group of researchers studied 380 bones belonging to 250 animals — some living, some extinct — including marine reptiles and flying reptiles, as well as mammals, lizards, crocodiles and birds.
“There are certain laws that apply to any organism on this planet. One of those laws is about density and the ability to submerge in water,” said Matteo Fabri, a postdoctoral researcher at Chicago’s Field Museum, in a press release. He was the lead author of the study, which was published Wednesday in the journal Nature.
The study said that bone density can be used as evidence of adaptation to life in the water, even aquatic animals that are not clearly formed for an aquatic lifestyle – such as the hippopotamus – have very dense bones.
The researchers found that spinosaurs – a family of predatory dinosaurs that could reach a height of 15 meters (49 feet) In length (greater than T. rex) – he had dense bones, which indicates that they have adapted to life in water. They said it was likely that none of the other 39 dinosaurs the research team examined as part of the study would have been comfortable in the water.
Spinosaurus’ relationship with water
Within the Spinosaurus family, they concluded that Spinosaurus, which has a sail-like feature on its spine, and its close relative Baryonyx, had increased bone density and was able to swim and fish while submerged underwater — somewhat like a crocodile or a hippopotamus. Sucomimus, another closely related dinosaur, had lighter bones that would make swimming more difficult. The study found that it likely lived by water and ate fish, as indicated by its crocodile-like nose and conical teeth, but judging by its bone density, it wasn’t actually swimming.
Spinosaurus’ gills It is not set at all as is in animals such as hippos and crocodiles, which spend most of their time submerged in water; Instead, it is placed back on the skull as in herons and other foraging animals by dipping their nose in water to feed,” said Holz, who was not involved in the study.
“The new evidence is consistent with his ability to dive, at least for some time. But as we showed in last year’s paper, he couldn’t be a really fast swimmer with that huge sail, at least not in water.”
Jason Ball, assistant professor at Drexel University and director of fossil preparation at the Bighorn Bassin Paleontological Institute, said he would have liked to see more Spinosaurus specimens included in the study.
“Oddball dinosaurs tend to provide insight into the extremes of dinosaur evolution,” said Ball, who was not involved in the research. “The more specimens there are, the better it is to understand how they got so weird.”
“I think this study is good for keeping the movement going but more work is always needed to get a better picture of the life of something very exotic and far in time.”
big data
Researchers, including scientists From the United States, Europe and Morocco, he first compiled a database of femur and rib bone sections from a variety of animals to understand whether there is a global association between bone density and behavior.
They cast a wide net. “We’ve included seals, whales, elephants, mice, and hummingbirds. We have dinosaurs of various sizes, and extinct marine reptiles like Mosasaurs and plesiosaurs. We have animals that weigh several tons, and animals of only a few grams. The spread is very large,” Fabry said.
They found that animals that submerge themselves underwater to find food have bones that are almost completely solid, while the cross-sections of the bones of land dwellers look more like cakes, with hollow centers.
They discovered that other dinosaurs, such as the perennial plant-eating sauropods, also had dense leg bones, but other bones were lighter in weight. This was a pattern also seen in very heavy live wild animals such as elephants and rhinos, Fabry said.
This research is an example of a big data approach to paleontology that has yielded intriguing insights into how dinosaurs experienced their world – something that is often difficult to verify by studying the fossils of individual animals.
Studies like this, according to Jingmaye O’Connor, Field Museum curator and co-author Studying bone density from hundreds of specimens is the “future of paleontology”.
“It takes a long time to do, but it has allowed scientists to shed light on large patterns, rather than making qualitative observations based on a single fossil.”
However, this type of research has limitations, because a single individual feature cannot give a complete picture of an animal’s lifestyle, Holz said.
“Each clue adds to the overall picture. In this particular case, they have provided a fantastic new database of bone density in a variety of animals with different lifestyle habits. So in the future we can now compare other animals with lifestyles that are not well understood,” said Holz.
