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New research shows that the largest predatory dinosaur to ever walk the Earth carried a huge sail rising from its back, but it turns out that this imposing creature could have made for a very slow and awkward swimmer.
Spinosaurus was larger than Tyrannosaurus rex at 45 feet (13.7 m) long. said Paul Serino, professor of biology and anatomy at the University of California, Illinois University of Chicago.
Spinosaurus primarily hunted very large fish, such as Sawfish, lungfish and Hollow, and had long, sickle-shaped hand claws for gripping and tearing. However, the tyrannosaurus was better adapted to life on land and hunting from beaches rather than filling the niche of an aquatic underwater predator, said Sereno, lead author of a new paper published Nov. 30 in the journal Nature. eLife.
“Do I think this animal would have been wading in the water on a regular basis? Sure, but I don’t think it was a good swimmer and incapable of full diving behavior,” Cerino said.
“This is simply not an animal that would be as dynamic in your wildest dreams above water as a much less swimmer underwater.”
Spinosaurus has always intrigued scientists.
German paleontologist Ernst Strummer Named prehistoric predator Spinosaurus aegyptiacus In 1915 after the first partial The skeleton was discovered by paleontologist Richard Markgrave in Egypt.
Strummer, who suggested the dinosaur stood upright on its hind legs and snacked on fish, displayed the find at the Munich Fossil Museum. The fossils were destroyed during Allied bombing in World War II, and only Strummer’s notes and drawings survive.
Several decades later, miners unearthed more fossils from sandstone rocks in southeastern Morocco. Sereno and his team studied the fossils, as well as museum specimens and Strummer’s original notes, and shared them Their findings in 2014.
A more complete depiction of the predatory dinosaur emerged as one with slashing, interlocking teeth ideal for hunting, a long neck and torso, short hind legs, and a towering sail made up of skin-covered dorsal spines.
The dinosaur’s small nose was placed farther into the skull. It enables it to breathe even when partially submerged in water. This anatomical evidence indicates that Spinosaurus was “semi-aquatic” and waded in shallow waters along river banks in search of its prey.
In recent years, other teams have published research as they study new fossils Spinosaurus was an entirely aquatic predator With a paddle-like tail that would have allowed it to move like an eel, and dense bones that acted as ballast, allowing it to dive deeply into the water column.
Sereno and his team are back in their work with Spinosaurus in search of answers about what life was really like for the fearsome dinosaur.
Sereno started running into an error in a 2014 paper. When he and his team calculated the dinosaur’s center of gravity, the software didn’t deduct enough mass to account for its lungs. This made it appear that spinosaurs would need to walk on all fours.
“I like to admit mistakes, especially when I can correct them myself,” said Cirino.
The team collected CT images of the skeleton of Spinosaurus and added layers of muscle and body mass, based on modern reptiles, to roughly build a new model. This time, Spinosaurus had a center of gravity above its hips and stood upright, like T-Rex and other towering predatory dinosaurs.
“The rigid limbs are not there for heft while swimming, but rather to support the great weight of the beast,” Serino said.
Next, the team switched to the tail of Spinosaurus. Dr. Frank Fish, an expert in tail mechanics and professor of biology at West Chester University in Pennsylvania, took the helm.
The fish compared the tail of Spinosaurus with that of crocodiles and other reptiles and found that the dinosaurs were too rigid to function well underwater. Whereas a crocodile folds its limbs while swimming and has the flexibility to rotate and roll underwater in search of prey, Spinosaurus’ massive body mass, long sail, and dangling hind legs would have been a hindrance.
“The back paddles are an order of magnitude too small to produce any subsequent rowing motion or force,” said Cirino. “No fully aquatic animals, on the contrary, have relatively large forelimbs like Spinosaurus, since the forelimbs are not very efficient as paddles.”
Its bony, muscular tail did not have the same flexibility as that of a whale or a fish, and the heavy sail was probably more of a hindrance than a useful tool.
If Spinosaurus were drowned in deeper waters, the results wouldn’t be very pleasant.
“He’ll break his chest, and die in a minute,” said Sereno, not to mention dragging his “very stiff sail and hanging limbs.” He would not have been able to catch fish by swimming after them.
So what is the purpose of a sail?
“The show is, like a billboard,” said Cirino. Similar to some lizards today that have spine-supported sails, he said, Spinosaurus likely used its sail during competition and courtship.
The fossil record also indicates that Spinosaurus was more adapted to rivers and lakes than oceans. Spinosaurus fossils have been found largely in riverbank sediments in the inland basins of Niger, far from prehistoric sea coasts.
It’s interesting that dinosaurs likely lived along freshwater and marine habitats like other semi-aquatic reptiles, but it’s not something that any of the other extinct or extant large aquatic vertebrates like ichthyosaurs or sea turtles did. So Spinosaurus prowled along coastal and inland waterways, ambushing prey as it waded through the shallows.
“Non-floating dinosaurs have dominated the world for 150 million years, but they never went into the water in a serious way,” Serino said. “Of course, they can swim like we can, but that doesn’t mean we’re aquatic. We’re talking about whether they really adapted to life in the water, and that’s the central question behind all this interest in Spinosaurus.”
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