A dinosaur larger than T. rex swam and hunted its prey underwater

New data on spinosaurus habits revealed 0:51 (CNN) — Dinosaurs were long thought to be land animals that stayed away from water.
A groundbreaking 2014 discovery of a spinosaurus with features that pointed to an aquatic lifestyle — retracted nostrils, short hind legs, a flipper-like tail and paddle-like feet — challenged that belief. However, the question of whether some dinosaurs actually felt comfortable in the water or simply stayed on the shore and dipped their heads to chase their prey like a heron would has divided paleontologists. In an attempt to resolve this heated debate, a group of researchers has studied 380 bones belonging to 250 animals, some living and some extinct, including marine reptiles and flying reptiles, as well as mammals, lizards, crocodiles and birds. “There are certain laws that are applicable to any organism on this planet. One of these laws concerns density and the ability to submerge in water,” Matteo Fabbri, a postdoctoral researcher at the Field Museum in Chicago, said in a press release. . He was the lead author of the study published Wednesday in the academic journal Nature. Bone density can be used as evidence of adaptation to life in the water, according to the study, since even aquatic animals that are not clearly shaped for an aquatic lifestyle, such as the hippopotamus, have very dense bones. Paleontologist Matteo Fabbri working on a fossil in the field. The researchers found that spinosaurs, a family of predatory dinosaurs that can grow up to 50 feet (larger than a T. rex), had dense bones, suggesting they were adapted to life in water. None of the 39 other dinosaurs the research team investigated as part of the study were comfortable in the water, they said. Spinosaurs’ relationship with water Within the spinosaur family, they concluded that Spinosaurus, which has a distinctive sail-shaped feature on its spine, and its close relative Baryonyx had higher bone density and they would have been able to swim and hunt while submerged underwater, a bit like a crocodile or hippopotamus. Suchomimus, another related dinosaur, had lighter bones that would have made it difficult for it to swim. It likely lived by the water and ate fish, as evidenced by its crocodile-like snout and conical teeth, but based on the density of its bones, it did not actually swim, according to the study. Thomas Holtz, senior professor of vertebrate paleontology at the University of Maryland, said the study confirmed that the ancestors of Spinosaurus and Baryonyx spent enough time in the water to develop a counterweight, to provide stability, in the form of dense bones. However, he said his work on Spinosaurus showed that it most likely hit the food from above, perhaps from the shore, or while drifting lazily on the surface of the water, and not by diving to depths. . “The Spinosaurus nostril is not positioned at all like it is in animals like hippos and crocodiles, which spend much of their time submerged; instead, it is positioned far back in the skull like in herons and other feeding animals.” dipping their snout into the water to feed,” said Holz, who was not involved in the study. “The new evidence is consistent with it being able to submerge, at least at some point. But as we showed in an article last year, it couldn’t be a really fast swimmer with that big sail, at least not in shallow water.” Jason Poole, an associate professor at Drexel University and director of fossil preparation at the Bighorn Basin Paleontological Institute, said he would have liked to see more Spinosaurus-related specimens included in the study. “Wacky dinosaurs often offer insight into the extremes of dinosaur evolution. The more specimens the better to understand how they got to be so weird,” said Poole, who was not involved in the research. “I think this study is good to move forward, but more work is always needed to get a better picture of the life of something so strange and far away in time.” The researchers analyzed the bone density of extinct and living animals. Big data push The researchers, including scientists from the United States, Europe and Morocco, first compiled a database of sections of thigh and rib bones from various animals to see if there was a universal correlation between bone density and behavior. The network they used was very wide. “We include seals, whales, elephants, mice, hummingbirds. We have dinosaurs of different sizes, extinct marine reptiles like mosasaurs and plesiosaurs. We have animals that weigh several tons and others that barely weigh a few grams. The dispersion is very large,” said Fabbri. They found that animals that dive underwater to find food have almost completely solid bones, while cross-sections of the bones of land dwellers look more like donuts, with hollow centers. They found that other dinosaurs, such as the towering plant-eating sauropods, also had dense leg bones, but other bones were lightweight. Fabbri said this was a pattern that was also seen in very heavy living land animals, such as elephants and rhinos. An illustration of Baryonyx walkeri, a spinosaurid from the United Kingdom, hunting and feeding. The research is an example of a big data approach in paleontology that has provided interesting insights into how dinosaurs experienced their world, something that is often difficult to determine from the study of individual animal fossils. These types of studies, based on hundreds of specimens, Jingmai O’Connor, curator of the Field Museum and co-author of the study on bone density, are “the future of paleontology.” “They take a long time, but they allow scientists to shed light on large patterns, rather than making qualitative observations based on a single fossil.” A study published last year examined and reconstructed the inner ears of ancient fossilized beasts and compared them to the ear canals of living animals. The researchers were able to deduce from that exercise whether the creatures would have been nocturnal hunters, attentive parents, or clumsy fliers. However, this type of research has limitations, as an individual characteristic cannot give a complete picture of an animal’s lifestyle, Holtz said. “Each piece of evidence adds to the total picture. In this particular case, they provided a large new database on bone density in a wide variety of animals of different habits. So in the future we will be able to compare other animals with different styles.” of life that are not well understood,” Holtz said.