Thick bones in the skeleton of Spinosaurus highly suggest it spent a considerable quantity of time submerged in the water. Like its much larger African relative Spinosaurus, Baryonyx had thick bones, recommending that it too invested much of its time submerged in water. The carefully related African Suchomimus had hollower bones. It still lived by water and ate fish, as evidenced by its crocodile-like snout and cone-shaped teeth, but based on its bone density, it wasnt actually swimming much. The bones do not lie, and now we know than even the internal architecture of the bones is completely constant with our interpretation of this animal as a huge predator hunting fish in vast rivers, utilizing its paddle-like tail for propulsion.
Spinosaurus, the longest predatory dinosaur known, is opening its elongate jaws, studded with conical teeth, to capture a sawskate. Dense bones in the skeleton of Spinosaurus highly suggest it invested a substantial amount of time submerged in the water.
Spinosaurus is the largest predatory dinosaur known– over two meters longer than the longest Tyrannosaurus rex– however the method it hunted has been a subject of dispute for decades.
In a new paper, released on March 23, 2022, in Nature, a group of paleontologists have actually taken a different method to figure out the lifestyle of long-extinct animals: examining the density of their bones.
By examining the density of spinosaurid bones and comparing them to other animals like hippos, penguins, and alligators, the group found that Spinosaurus and its close relative Baryonyx from the Cretaceous of the UK both had dense bones that would have enabled them to submerge themselves undersea to hunt.
Researchers currently knew that spinosaurids had certain affinities with water– their lengthen jaws and cone-shaped teeth resemble those of fish-eating predators, and the ribcage of Baryonyx, from Surrey, even contained half-digested fish scales.
In the last decade, University of Portsmouth paleontologist and National Geographic Explorer Dr. Nizar Ibrahim unearthed different parts of a Spinosaurus skeleton in North Africas Sahara Desert. The skeleton Dr. Ibrahim and his team described had actually withdrawed nostrils, brief hind legs, paddle-like feet, and a fin-like tail: all signs that strongly pointed to a marine lifestyle.
Dr. Ibrahim said: “We fought sandstorms, flooding, snakes, scorpions, and more to excavate the most enigmatic dinosaur on the planet and now we have several lines of proof all pointing in the same direction– the skeleton actually has “water-loving dinosaur” composed all over it!”
Baryonyx, from Surrey in England, swims through an ancient river with a fish in its jaws. Like its much larger African relative Spinosaurus, Baryonyx had dense bones, recommending that it too spent much of its time immersed in water. It was formerly believed to have been less aquatic than its Saharan relative. Credit: Davide Bonadonna
Based upon its highly specialized anatomy, Dr. Ibrahim and his team formerly suggested that Spinosaurus might swim and actively pursue victim in the water, but others declared that it was not much of a swimmer and instead waded in the water like a huge heron.
Researchers have actually continued to dispute whether Spinosaurus invested much of its time submerged, pursuing prey in the water, or if it simply stood in the shallows and dipped its jaws in to snap up prey.
” In part this is probably since we were challenging decade-old dogma– so even if you have a really strong case, you kind of anticipate a particular degree of pushback,” Dr Ibrahim said.
This continuing argument led lead author Dr. Matteo Fabbri, based at Chicagos Field Museum, senior author Dr. Ibrahim and a global group of scientists to try to discover another method to presume the way of life and ecology of long-extinct creatures like Spinosaurus.
Dr. Nizar Ibrahim. Credit: Paolo Verzone.
Dr. Fabbri stated: “The concept for our research study was, alright, clearly we can analyze the fossil information in different ways. What about the basic physical laws? There are certain laws that apply to any organism on this planet. Among these laws regards density and the ability of submerging into water.”.
Throughout the animal kingdom, bone density can tell us whether an animal is able to sink beneath the surface and swim.
” Previous research studies have revealed that mammals adapted to water have thick, compact bone in their postcranial (behind the skull) skeletons,” said Fabbri, a specialist on the internal structure of bone. Dense bone assists with buoyancy control and permits the animal to submerge itself.
The group assembled a large dataset of femur and rib bone cross-sections from 250 types of living and extinct animals, consisting of both land-dwellers and water-dwellers, and covering animals ranging in weight from a few grams to numerous tonnes consisting of seals, whales, elephants, mice, and even hummingbirds.
They likewise gathered information on extinct marine reptiles like mosasaurs and plesiosaurs. The scientists compared bone cross areas of these animals to cross-sections of bone from Spinosaurus and its relatives Baryonyx and Suchomimus.
Dr. Ibrahim said: “The scope of our study kept broadening due to the fact that we kept thinking of more and more groups of vertebrates to include.”.
The researchers found a clear link in between bone density and water foraging behavior: animals that submerge themselves underwater to find food have bones that are nearly totally strong throughout, whereas cross-sections of land-dwellers bones look more like doughnuts, with hollow centers.
When the researchers applied spinosaurid dinosaur bones to this paradigm, they found that Spinosaurus and Baryonyx both had the kind of thick bone associated with complete submersion.
The carefully related African Suchomimus had hollower bones. It still lived by water and ate fish, as evidenced by its crocodile-like snout and conical teeth, however based on its bone density, it wasnt actually swimming much.
Other dinosaurs, like the giant long-necked sauropods also had some thick bones in their limbs, but this merely shows the substantial amount of stress on those limb bones.
Dr. Ibrahim said: “Some of these animals would have weighed as much as numerous elephants so including extra load-bearing capacity to the bones makes a great deal of sense!”.
Dr. Jingmai OConnor, a curator at the Field Museum and co-author of this study, states that collective studies like this one that draw from hundreds of specimens, are “the future of paleontology. Theyre very lengthy to do, but they let researchers shed light onto huge patterns.”.
“I believe that, with this extra line of proof, speculative concepts that imagine Spinosaurus as some sort of huge wader lack evidential assistance and can be securely omitted. The bones do not lie, and now we understand than even the internal architecture of the bones is entirely consistent with our analysis of this animal as a huge predator hunting fish in vast rivers, using its paddle-like tail for propulsion.
For more on this research study, see Dense Bones Allowed Spinosaurus– The Biggest Carnivorous Dinosaur Ever Discovered– To Hunt Underwater.
Reference: “Subaqueous foraging amongst carnivorous dinosaurs” by Matteo Fabbri, Guillermo Navalón, Roger B. J. Benson, Diego Pol, Jingmai OConnor, Bhart-Anjan S. Bhullar, Gregory M. Erickson, Mark A. Norell, Andrew Orkney, Matthew C. Lamanna, Samir Zouhri, Justine Becker, Amanda Emke, Cristiano Dal Sasso, Gabriele Bindellini, Simone Maganuco, Marco Auditore and Nizar Ibrahim, 23 March 2022, Nature.DOI: 10.1038/ s41586-022-04528-0.
