Tyrannosaurus Rex

Tyrannosaurus is a genus of Tyrannosaurid from the Late Cretaceous of North America. It's name means "Tyrant lizard King", it's not difficult to see why. At an average 13 meters and 8 tons ; with a maximum length and weight of 16 meters and 10 tons, It's truly massive.

Tyrannosaurus had banana sized bone crushing teeth. While they did possess a point, their main function was for bone crushing and tearing. It is estimated these giants had a bite force of around 8 tons! A bite from a 45 foot animal with those jaws would be devastating. With that, Tyranosaurus could prey on anything it wanted.

Rex was an apex predator. It sat on top of a food chain with no other large bodied predators to compete with. The next largest was Nanotyrannus(who i will address in a second), followed by Dromaeosaurus. Prey wasn't that easy to take down, though. Animals like Triceratops, an African Rhino on steroids with horns to match, and Ankylosaurus, an ancient version of a tank. Hadrosaurs like Edmontosaurus, and the gargantuan sauropod Alamosaurus lumbered on the plains of Late Cretacous North America.

It has long been disputed that Nanotyrannus is just a juvenile Tyrannosaurus. In my opinion, that's just not the case. There are several anotomical differences, including:

-  N. lancensis had 14-15 teeth in each side of the upper jaw and 16 teeth in each side of the lower jaw . T. rex, on the other hand, had 11-12 tooth positions in the upper jaw and 11-14 in the lower.

- The skull of N. Lancensis has an orientation more pointed towards the ground, compared to T.rex, who held its head horizontal to the ground. Indeed, a Ct scan of N.Lancensis showed the brain orientation to be different then that in Rex.

- N. lancensis has a small pit in the quadratojugal, a bone in the back corner of the skull. Both the holotype and the "Jane" specimen have this feature, suggesting it is not a deformity, and it is not known in any adult tyrannosaurids.

It's all still open for debate, and there are those who still believe Nanotyrannus is a Juvenile Tyrannosaurus, just like most things in Paleontology. What we do know is Tyrannosaurus was one of the largest land carnivores to ever exist, and it's name is already heavily engraved in todays culture.