Washington, Sep 18 (Inditop.com) Researchers have unearthed a tiny T. rex predecessor in China, weighing only a hundredth of its much larger and more ferocious dinosaur descendant, popularised by the movie “Jurassic Park”.
The tiny T. rex predates its more powerful cousin by tens of millions of years. This finding means that such specialised physical features did not evolve as the prehistoric predators grew in size.
Instead, they were present for feeding efficiency at all sizes of the dinosaurs during their reign in the Cretaceous Period.
Paul Sereno from the University of Chicago, along with colleagues, studied the new, small-bodied fossil, naming it Raptorex kriegsteini, and estimated that it was a young adult when it died.
They examined the skull, teeth, nose, spine, shoulders, forearms, pelvis, and hind legs of the new fossil, comparing the features to larger evolutionary versions of tyrannosauroid dinosaurs.
“First, we used the best mechanical preparation of the specimen possible, which entails the finest needles and air abrasives under a microscope,” Sereno said.
“Then we made moulds and casts of the cranial bones, assembled a cast skull, and sent that skull through a CT scanner at the University of Chicago hospital to get the snout cross-section.”
“We used silicone on the skull roof to cast the forebrain of R. kriegsteini. Finally, I made a thin-section from one femur, or thigh bone, for microscopic examination, and determined that the individual had lived to be five or six years old.”
The researchers conclude that the “predatory skeletal design” of R. kriegsteini was simply scaled up with little modification in its carnivorous descendants, whose body masses eventually grew 90 times greater.
These findings were published online in the journal Science.
