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Researchers might have finally solved the mystery of holes in the head of tyrannosaurus rex

Researchers might have finally solved the mystery of holes in the head of tyrannosaurus rex

We generally perceive Tyrannosaurus rex as a ferocious animal always seething with rage. However, a new study has indicated that the presence of two mysterious holes on its skull might have helped in controlling the temperature inside its head. The work appears in The Anatomical Record

Earlier these holes also termed as dorsotemporal fenestra were considered to be only occupied by muscles which helped in the operation of its jaw. Casey Holliday, an anatomist from the University of Missouri said that it was strange for a muscle to extend from the jaw till the top of the skull. But now enough evidence has been gathered from alligators and other reptiles which suggest the presence of blood vessels in this region. Similar fenestra has been observed in the skulls of animals collectively termed as diapsids. It includes crocodilians, birds, lizards, and tuatara. It is estimated that the holes evolved nearly 300 million years ago. Fenestra can be found in tyrannosaurs and pterosaurs. The team analyzed several diapsid skulls to find out which animals had fenestra resembling T.rex; the closest one was crocodilians. 

Holliday and his team members, William Porter, Lawrence Witmer from Ohio University and Kent Vliet, University of Florida used thermal cameras for studying alligators at St Augustine Alligator Farm Zoological Park. The body temperature of alligators is dependent on the temperature of the surroundings since they are cold-blooded. As a result of which their thermoregulation processes are different from the warm-blooded or endothermic animals. 

“We noticed when it was cooler and the alligators are trying to warm up, our thermal imaging showed big hot spots in these holes in the roof of their skull, indicating a rise in temperature,” Vliet said.

“Yet, later in the day when it’s warmer, the holes appear dark, like they were turned off to keep cool. This is consistent with prior evidence that alligators have a cross-current circulatory system – or an internal thermostat, so to speak.”

It is not sure if dinosaurs were endothermic or ectothermic and this is a topic of heavy debate. Some scientists think they were in between the two categories i.e a feature called mesothermy. Previous research suggested that armoured ankylosaur had tunnels in the skull for keeping the brain at optimum temperatures.

It is suggested that T.rex use few thermoregulation tactics of the ectotherms. It can, however, be confirmed that there are no osteological features on the skull of tyrannosaurus which shows that fenestra were extensions of muscle attachment. They can also infer, based on modern alligators that Fenestra could have been used for controlling the temperature in the skull of T.rex by warming or cooling the blood flowing through blood vessels. 

Witmer said that similar to T.rex, alligators have holes on their skull-tops which are filled with blood vessels. But still, muscles have been grouped with dinosaurs. The anatomy and physiology of the present-day animals can be used to discard the early hypotheses.

Journal Reference: The Anatomical Record

Tyrannosaurus rex

Largest Tyrannosaurus Rex (T-Rex) skeleton found in Canada

Palaeontologists from the University of Alberta have recently unearthed a skeletal frame of Tyrannosaurus rex, which is reportedly the largest dinosaur skeleton ever found in Canada. The skeleton is 13 meters long has been nicknamed as “Scotty”. It is believed that the dinosaur belonged to prehistoric Saskatchewan almost 66 million years ago.

Scotty measures 13 meters, that is 43 feet from its nose to tail tip, and would have cracked the scales at 8800 kgs that is 19400 pounds, based on a calculation by evaluating its thigh bones. The bones are not actually new. They had been discovered in Saskatchewan in 1991, but since they were embedded in some pretty solid sandstone, the excavation was a slow and painstaking process which took almost a decade to be completed.

Paleontologists can figure out the health and type of functioning by looking at a dinosaur’s bones. By looking into their bones and cutting into them, one can figure out their health pattern as well. Annual variations in climate and food availability would slow dinosaurs’ bone growth, which results in a ring. These rings – much like the rings of a tree trunk are determined to estimate a dinosaur’s age at the time of his death. By Tyrannosaurus standards and norms, “it had a very unusually long life“. Paleontologists estimated that it died in its early 30s.

Scotty’s bones also had extensive injuries that showed signs of healing. Which means the old animal who lived 66 million years ago in the Cretaceous, got into a lot of scrapes and movement – and somehow survived them. The injuries and bruises were violent and riddled across the skeleton.

Among Scotty’s body injuries, a few are broken ribs, an infected jaw, and what may be a bite from another Tyrannosaurus rex on its tail, showing evidence of a few battle scars from a long life.

A new exhibit featuring the skeleton of the newly excavated dinosaur is all set to open for the public at the Royal Saskatchewan Museum in May 2019.