Temporal range: Late Cretaceous
|Teeth from South Dakota assigned to T. formosus, with a US dime coin for scale, Children's Museum of Indianapolis|
| †Troodon formosus|
Troodon (Troödon in older sources) is a dubious genus of relatively small, bird-like dinosaurs known definitively from the Campanian age of the Cretaceous period (about 77 mya). It includes at least one species, Troodon formosus, is known from Alberta and Montana. Discovered in 1855, T. formosus was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877.
The genus name is Greek for "wounding tooth", referring to the teeth, which were different from those of most other theropods known at the time of their discovery. The teeth bear prominent, apically oriented serrations. These "wounding" serrations, however, are morphometrically more similar to those of herbivorous reptiles, and suggest a possibly omnivorous diet.
For a long time, Stenonychosaurus inequalis was thought to be a synonym of Troodon formosus or a separate species, T. inequalis, but a 2017 study by Aaron J. van der Reest and Phillip Currie revived the genus.. The same paper noted that Troodon lacked any features separating it from most troodontids and suggested that Troodon formosus should be a nomen dubium.
DiscoveryEditThe Troodon tooth was originally classified as a "lacertilian" (lizard) by Leidy, but reassigned as a megalosaurid dinosaur by Nopcsa in 1901 (Megalosauridae having historically been a wastebin taxon for most carnivorous dinosaurs). In 1924, Gilmore suggested that the tooth belonged to the herbivorous pachycephalosaur Stegoceras, and that Stegoceras was in fact a junior synonym of Troodon (the similarity of troodontid teeth to those of herbivorous dinosaurs continues to lead many paleontologists to believe that these animals were omnivores). The classification of Troodon as a pachycephalosaur was followed for many years, during which the family Pachycephalosauridae was known as Troodontidae. In 1945, Charles Mortram Sternberg rejected the possibility that Troodon was a pachycephalosaur due to its stronger similarity to the teeth of other carnivorous dinosaurs. With Troodon now classified as a theropod, the family Troodontidae could no longer be used for the dome-headed dinosaurs, so Sternberg named a new family for them, Pachycephalosauridae.
Scientists at a British university later conducted a thought experiment related to the evolution of Troodon, had it not been so brutally wiped out by the cataclysmic meteorite impact of 65 million years ago. The scientists
discovered that, as Troodon's eyes grew, his head would have to frequently bend upwards to gain a better view. The only way to solve that problem was to change the angle at which the spine was to the ground, in other words, to become erect. With Troodon standing upright, there would be no need for a tail to act as a counterbalance, henceforth reducing the requirement for a tail. Troodon had become humanoid. Although this is just a thought experiment, it really does give a fascinating glimpse of what evolutionary paths certain lineages of dinosaur may have taken to, had they not been eradicated. This little carnivore was a relative of Saurornithoides, another type of Troodontid.
In 2017, Aaron J. van der Reest and Currie resurrected Stenonychosaurus as a valid genus.
In the MediaEdit
- Troodon has become a popular dinosaur in prehistoric culture. It's featured in many documentaries, such as Planet Dinosaur, March of the Dinosaurs, Dinosaur Revolution, and Dinosaur Planet. It's also been in books such as Dinotopia and even in Jurassic Park: The Game. Some Troodon appeared in Prehistoric Park, March Of The Dinosaurs AKA The Great Dinosaur Escape, Walking With Dinosaurs: The 3D Film, Ice Age: Dawn of the Dinosaurs, Giant Screen Films Waking the T. Rex: The Story of SUE, Minor appearances in PBS The Dinosaurs!, The 1st episode of the Six part PBS NATURE Program Triumph of Life and You Are Umasou.
- Troodon is metioned in The Lost World novel. John Roxton discovered what he believed to be a Velociraptor skeleton in Mongolia. However, it was actually a Troodon skeleton (even though the Troodon genus is only found in North America, although there are troodonids in Asia). The fossil discovered had impressions of its skin.
- Troodon is one of the available dinosaurs on the IOS application, Jurassic Park: Builder. The Troodon uses the same animations of Compsognathus and Velociraptor.
- Troodon was added to Jurassic World: The Game on January 4, 2016, but is a limited tournament dinosaur. It is a legendary carnivore. While it is accurately portrayed with a coat of feathers, it is shown inaccurately to be able to pronate it's hands.
- A pack of Troodons can be seen in Jurassic Park The Game at the beginnig and in other parts of the game. They are said to be very toxic in the game.
- It will appear in ARK: Survival Evolved. While it is accurately portrayed with a coat of feathers, it is shown inaccurately to be able to pronate it's hands.
- Troodon also appeared in Fantasia attacking an Archaeopteryx. While many viewers assume it was an Ornitholestes, the scripts confirm it's a Troodon. Also in the film, Troodon is depicted as having a domed head and horns, since at that time it was assumed to be a pachycephalosaur.
- Kate Elliot's Spiritwalker book trilogy features 'trolls' that she acknowledges being descended from Troodon.
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