Fearsome spinosaurus wasn't the scourge of prehistoric seas after all - CNN

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The largest predatory dinosaur to ever locomotion connected Earth sported a monolithic sail that roseate from its back, but it turns retired this imposing carnal would person made for a precise dilatory and awkward swimmer, according to caller research.

Spinosaurus was adjacent larger than Tyrannosaurus rex and measured 45 feet (13.7 meters) long. The colossus had an antithetic skull signifier that made it look much similar a toothy crocodile than a raptor, said Paul Sereno, prof of organismal biology and anatomy astatine The University of Chicago.

Spinosaurus chiefly hunted precise ample fish, specified as sawfish, lungfish and coelacanths, and had long, scythe-shaped manus claws to drawback and rip them apart. However, the dinosaur was much adapted to beingness connected onshore and hunting from shorelines alternatively than filling the niche of an aquatic, underwater predator, said Sereno, pb writer of a caller insubstantial published November 30 successful the diary eLife.

“Do I deliberation that this carnal would person waded into h2o connected a regular basis? Absolutely, but I don’t deliberation it was a bully swimmer nor susceptible of afloat submergence behavior,” Sereno said.

“This is simply not an carnal that successful your wildest dreams would beryllium dynamic supra h2o arsenic a swimmer overmuch little underwater.”

Spinosaurus has agelong intrigued scientists.

German paleontologist Ernst Stromer named the prehistoric predator Spinosaurus aegyptiacus successful 1915 aft the archetypal partial skeleton was discovered by his fossil huntsman Richard Markgraf successful Egypt.

Stromer, who suggested the dinosaur stood upright connected its backmost legs and snacked connected fish, displayed the find successful Munich’s Paleontological Museum. The fossils were destroyed during Allied bombing successful World War II, and lone Stromer’s notes and drawings survived.

Many decades later, much fossils were unearthed by miners from the sandstone rocks of southeastern Morocco. Sereno and his squad studied the fossils, arsenic good arsenic specimens from museums and Stromer’s archetypal notes, and shared their findings successful 2014.

A much implicit depiction of the predatory dinosaur emerged arsenic 1 with interlocking slanted teeth cleanable for catching fish, a agelong cervix and trunk, abbreviated backmost legs and a towering sail made up of dorsal spines covered successful skin.

The dinosaur’s tiny nostrils were acceptable backmost farther successful the skull, enabling it to respire adjacent erstwhile partially submerged successful the water. This anatomical hint suggested Spinosaurus was “semiaquatic” and waded into the shallow waters on stream banks for its prey.

In caller years, different teams person published probe arsenic they studied caller fossils that suggested Spinosaurus was a afloat aquatic predator with a fleshy paddle-like process that would person allowed it to determination similar an eel, and dense bones that acted arsenic ballast, allowing it to dive heavy into the h2o column.

Sereno and his squad returned to their enactment with Spinosaurus successful hunt of answers astir what beingness had truly been similar for the fearsome dinosaur.

Sereno began by confronting a mistake successful the 2014 paper. When helium and his squad calculated the dinosaur’s halfway of gravity, the bundle didn’t deduct capable wide to relationship for its lungs. This made it look similar Spinosaurs would request to locomotion connected each fours.

“I emotion to admit mistakes, particularly erstwhile I tin close them myself,” Sereno said.

The squad collected CT scans of the Spinosaurus skeleton and added layers of musculature and assemblage mass, based connected modern reptiles, to virtually conception a caller model. This time, Spinosaurus had a halfway of gravity implicit its hips and stood upright, overmuch similar T. rex and different towering dinosaur predators.

“The coagulated limbs are not determination for ballast portion swimming, but alternatively to enactment the large value of the beast,” Sereno said.

Next, the squad turned to Spinosaurus’ tail. Dr. Frank Fish, process mechanics adept and prof of biology astatine West Chester University of Pennsylvania, took the lead.

Fish compared the Spinosaurus process with those of alligators and different reptiles and recovered the dinosaur would person been excessively rigid to relation good underwater. While alligators tuck their limbs successful arsenic they aquatics and person the flexibility to rotation and rotation underwater successful pursuit of prey, Spinosaurus’ immense assemblage mass, gangly sail and dangling hind legs would person been a hindrance.

“The hind paddles are an bid of magnitude excessively tiny to nutrient immoderate consequential paddling question oregon power,” Sereno said. “No afloat aquatic animals, conversely, has forelimbs arsenic proportionately ample arsenic Spinosaurus, arsenic the beforehand limbs are precise inefficient arsenic paddles.”

Its bony, muscular process wouldn’t person had the aforesaid flexibility of a whale oregon fish, and the dense sail mightiness person been much of an obstacle than a utile tool.

If Spinosaurus was plunked down successful heavy water, the results wouldn’t person been precise pleasant.

“Its thorax would beryllium crushed, and it would dice wrong a minute,” Sereno said, not to notation the resistance of its “super ungainly stiff sail and hanging limbs.” And it wouldn’t person been capable to drawback food by swimming aft them.

So what was the intent of the sail?

“Display, similar a billboard,” Sereno said. Similar to immoderate lizards contiguous that person spine-supported sails, Spinosaurus apt utilized its sail during contention and courtship, helium said.

The fossil grounds besides suggests Spinosaurus was much adapted to rivers and lakes than oceans. Spinosaurus fossils person mostly been recovered successful the riverbank deposits of Niger’s inland basins, which are distant from prehistoric marine coastlines.

Intriguingly, the dinosaur apt lived on marine and freshwater habitats similar different semiaquatic reptiles, but it’s not thing that immoderate different extinct oregon extant ample aquatic vertebrates similar ichthyosaurs oregon oversea turtles did. So Spinosaurus would person prowled on coastal and inland waterways, ambushing prey arsenic it waded into shallow waters.

“Nonavian dinosaurs dominated the satellite for 150 cardinal years, but they ne'er went into the h2o successful a superior way,” Sereno said. “Of course, they could aquatics conscionable similar we do, but that doesn’t mean we’re aquatic. We’re talking astir whether they were genuinely adapted to beingness successful the water, and that’s the cardinal question down each this attraction connected Spinosaurus.”