The new dinosaur was named after the Greek god of death, Thanatos, and theristes, which translates to 'one who reaps or harvests', hence the English translation, Reaper of Death.
Calgary PhD student Jared Voris discovered the new species, whilst the bones were found by John and Sandra De Groot in 2010 near the town of Hays. Voris was researching a different species when he realised that no tyrannosaurs had come from the area in which the bones were found. Following this, he also noticed key differences between the bones and other known T-Rex species.
This apex predator was found in Alberta, but at the time of its survival (the Cretaceous period), the Reaper of Death would have been roaming a swampy region of the Western Interior Seaway that divided the Arctic and Gulf of Mexico.
Darla Zelenitsky, assistant professor of dinosaur palaeobiology at the University of Calgary, said, "There are very few species of tyrannosaurids, relatively speaking. Because of the nature of the food chain, these large apex predators were rare compared to herbivorous or plant-eating dinosaurs" and so the find is beyond belief.
The scientists at the University of Calgary believe this to be the oldest member of the T-Rex family that has been discovered thus far, and it is said to have been able to grow to a staggering length of 26ft or 8m.
We chose a name that embodies what this tyrannosaur was as the only known large apex predator of its time in Canada, the Reaper of Death. The nickname has come to be Thanatos.Darla Zelentisky, Assistant Professor of dinosaur palaeobiology at the University of Calgary
The T-Rex was known to be active around 66 million years ago, whilst the Reaper of Death dates back even further at 79 million years. Thanatos was also found to have a longer and deeper snout, which is comparable to the more primitive tyrannosaurs that lived in the south of what is now the USA.
They knew that this was a different species as it had ridges along the upper jaw which distinguished the fossil from other known dinosaurs. Researchers believe that the two species may have had different skulls due to their differing diets, such as the prey that they may have hunted at the time. Different environments would naturally cause the two variants of T-Rex to evolve differently.
With this new species, we now know that tyrannosaurs were present in Alberta prior to 77 million years ago, the age of the next-oldest tyrannosaur.Co-author of the study, Dr Francois Therrien
François Therrien, the co-author, explained, "This discovery is significant because it fills in a gap in our understanding of tyrannosaur evolution."
Featured image credit: Royal Tyrrell Museum