(December Paladin)

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02/28/2012 17:11:48

Theropod Of The Day: Tyrannosaurus rex
→ Photo above by subarcticmike on Flickr.
→ T.O.T.D. posts written by crownedrose.

Tyrannosaurus rex may as well be the most famous dinosaur to have ever walked the Earth. Its name means “tyrant lizard” in Greek, and rex is “king” in Latin which was pinned by Henry Fairfield Osborn back in 1905, and the massive theropod sure lives up to its name! Below is some interesting information about T. rex for all to enjoy.

⁌ T. rex lived during the Late Cretaceous Period (67-65 Mya) as many know, roaming what is now the western parts of the United States of America and Canada. They measured to be slightly over 40 feet long at maximum, with powerful and elongated hind legs that show an ability to allow a decent speed for such a robust animals. There’s also the thick tail to help with balance, and the iconic (but short) S-shaped neck you see in theropods.

⁌ Contrary to popular belief, T. rex had forelimbs that were not useless. Theories have been brought to the table that they were used during mating rituals, or perhaps to hold down prey (dead or alive). Studying these specimens, T. rex forelimbs show a considerable amount of muscle attachments, making these forelimbs much stronger than previously thought; perhaps being able to curl over 400 pounds with each two digit hand! Not so wimpy anymore, right?

⁌ The tyrannosaur above is nicknamed “Black Beauty” because of the magnesium rich (and well preserved) skeleton, which is on display at the Royal Tyrrell Museum in Alberta, Canada.

⁌ Many know and have heard of Tyrannosaurus “Sue”, which is my favourite dinosaur skeleton in the world! She is the largest, most complete, and best preserved Tyrannosaurus rex ever discovered. Her skeleton has given us an endless amount of information towards the life and biomechanics of tyrannosaurids, and dinosaurs in general of the Mesozoic. You can read extra information I’ve written up about Sue here.

⁌ Unlike their depiction in Jurassic Park, Tyrannosaurus rex had binocular vision, which gave them great eyesight to hunt and scavenge for their prey. If you look at their skull, it is shaped like a triangle; the front of the skull is slender which then widens out to the back of the skull. This structure helped T. rex to have this vision, which suggests that it was a hunter. Many years ago it was thought T. rex only scavenged for food, but the hunter/scavenger debate is one that still goes on to this day in palaeontology, plus the theories of Tyrannosaurus engaging in cannibalism is on the table!

⁌ Ever heard of their teeth being called ‘bananas’? Tyrannosaurus had teeth with heterodonty, which means that their teeth changed shape depending on their position in the jaws (just like us)! Everyone knows the teeth T. rex had, which are massive, thick with reinforced ridges, and shaped like bananas which in tandem with the jaw power of T. rex, made for a deadly crushing bite. The premaxillary teeth at the front of the jaws helped as well for them to not break off during feeding due to their shape (and those ridges!). T. rex as well also replaced teeth, just like sharks do. We’ve found this out because of well preserved fossils that show new teeth coming in around full grown ones.

⁌ Their skull is one to be reckoned with, evolution having a field day to make for a powerful killer. Unlike other theropods, T. rex had a U-shaped upper jaw at the tip, strengthening its power to create bone crushing jaws which could deal with much stress in tearing off meat. Having such a massive skull would be heavy, but luckily (like other theropods), T. rex had many ways to lighten the weight by having large openings in the skull, along with certain bones showing to be fused and have skeletal pneumaticity. Read more about theropod skull comparison here.

⁌ The growth rate of T. rex was very fast, and one of the most changing during their lifetime. If you compare a youngster and adult tyrannosaur, you will see how much they morph. From having knife-like teeth and elongated heads when young, they grow up to have a much wider and robust head with those banana teeth like I stated above. Because of this dramatic change, some discoveries of young tyrannosaurs are thought to be a new genus of tyrannosauridae (ever hear of Nanotyrannus?). Many still debate whether or not Nanotyrannus (and even other tyrannosaurs) is a new genus, and more research is still being done to weave out these questions.

Also, I just want to end this post with a big thank you to everyone who has encouraged me to write this series, and for reading my ridiculously long posts! I tend to get very excited when I write these up, and I tried my best not to go too in depth on every aspect of Tyrannosaurus rex, though it all is extremely interesting. If anyone would like more information on T. rex - like locomotion, anatomy, feeding habits, fossil history, etc - just send me a message! I’m always willing to answer questions on theropods for the curious minds out there. I hope you all have enjoyed reading this, and be sure to keep a look out for future T.O.T.D. posts!

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