A dinosaur bigger than T. rex swam and hunted its prey underwater
In an attempt to resolve this heated debate, a group of researchers has studied 380 bones belonging to 250 animals — some living and others 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 regards density and the capability of submerging into water,” said Matteo Fabbri, a postdoctoral researcher at the Field Museum in Chicago, in a news release. He was the lead author of the study that published Wednesday in the journal Nature.
Bone density can be used as evidence for adaptation to life in water, the study said, as even aquatic animals that are not clearly shaped for an aquatic lifestyle — such as the hippopotamus — have very dense bones.
The researchers found that spinosaurids — a family of predatory dinosaurs that can be up to 15 meters (49 feet) in length (larger than a T. rex) — had dense bones, suggesting they were adapted to life in the water. None of the other 39 dinosaurs the research team investigated as part of the study were likely at ease in water, they said.
Spinosaurids’ relationship with water
Within the spinosaurid family, they concluded that Spinosaurus, which has a distinctive sail-like feature on its spine, and its close relative Baryonyx had increased bone density and would have been able to swim and hunt while submerged underwater — a bit like a crocodile or hippo. Suchomimus, another related dinosaur, had lighter bones that would have made swimming more difficult. It likely lived by water and ate fish, as evidenced by its crocodile-like snout and conical teeth, but based on its bone density, it wasn’t actually swimming, the study found.
“The nostrils of Spinosaurus is not at all placed like it is in animals like hippos and crocs, which spend much of their time submerged; instead, it is placed back on the skull as it is in herons and other animals which feed by dipping their snout in the water to feed,” said Holz, who wasn’t involved in the study.
“The new evidence is consistent with it being able to submerge, at least sometime(s). But as we showed in a paper last year, it couldn’t have been a really fast swimmer with that large sail, at least not in shallow water.”
Jason Poole, an adjunct professor at Drexel University and the Bighorn Basin Paleontological Institute’s director of fossil preparation, said he would have liked to see more specimens related to Spinosaurus included in the study.
“Oddball dinosaurs tend to offer insight into the…
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