Troodon

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{{Taxobox | color = pink | name = Troodon | status = Conservation status: Fossil | image = Troodont.jpg | image_width = 200px | regnum = Animalia | phylum = Chordata | classis = Sauropsida | ordo = Saurischia | subordo = Theropoda | familia = Troodontidae | genus = Troodon | binomial = Troodon formosus | binomial_authority = Leidy, 1856 }}

Troodon was a relatively small, bird-like dinosaur from the late Cretaceous Period (75-65 mya). Discovered in 1855, it was among the first dinosaurs found in North America, and is believed to have been one of the most intelligent.

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Characteristics

This small dinosaur was around 2 m (6.5 ft) in length, 1 m (3 ft) tall, and weighed 60 kg (130 lb). Its eyes were large (perhaps suggesting nocturnal activity) and slightly forward facing, giving Troodon some depth perception.

Troodon (pronounced "Tro-odon") is Greek for "wounding tooth", and refers to the dinosaur's serrated teeth (though these may actually have been adapted for herbivory, see below). Its diet consisted of smaller animals, including mammals and perhaps a significant amount of plant material as well.

Troodon had long arms that folded back like a bird's, and its hands possessed partially opposable thumbs. It had large, sickle-shaped claws on its second toes which were raised off the ground when running. This claw is common in the group Maniraptora, to which Troodon belongs.

Troodon had one of the largest known brains of any dinosaur relative to its body mass (comparable to modern birds). Eggs have also been discovered, in nests.

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Distribution

Troodon is known from the Judith River Formation of Montana, the Judith River Group of Alberta, the Horseshoe Canyon Formation of Alberta, and the North Slope of Alaska. There is some evidence that Troodon favored cooler climates, as it seems to have been particularly abundant in northern areas and during cooler intervals such as the Early Maastrichtian. It seems unlikely that all of these fossils- which come from localities hundreds or thousands of miles apart, separated by millions of years of time- represent a single species of Troodon. However, further study and more fossils are needed to determine how many species of Troodon existed.

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Biology

Troodon has very long, slender limbs suggesting that the animal was quite fast. Although originally thought to be a predator, there is some evidence that Troodon may either have been an omnivore or a herbivore. The jaws meet in a broad, U-shaped symphysis similar to that of an iguana, and the teeth are leaf-like, bearing large serrations like those of herbivorous dinosaurs. In addition, the teeth are short but broad, and bear wear facets on their sides; in these respects Troodon is again more like plant eating dinosaurs than carnivores such as Dromaeosauridae. A specimen of Troodon is known from Montana sitting atop a clutch of eggs.

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Classification

Troodon was first named Troödon (with a diaeresis) by Joseph Leidy in 1856, which was officially emended to its current status by Sauvage in 1876 — though both versions persist in common usage.

Troodon is known only from fossil teeth, which have since been conflated with postcranial material from specimens known as Stenonychosaurus. However, it has been disputed that the two species are one and the same.

A more detailed classification scheme:

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Intelligent Dinosaurs

In 1982, Paleontologist Dale Russell, curator of vertebrate fossils at the National Museums of Canada in Ottawa, speculated on how evolution would have proceeded if the troodonts had survived the extincton of the dinosaurs. Russell speculated that a species like Troodon would have grown smarter and taken on a human-like appearance. Russell partnered with taxidermist and artist Ron Sequin and together they made a model of what a derived, intelligent Troodon would look like, naming their fantasy creation a "Dinosauroid".

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References

es:Troodon fr:Troödon nl:Troodon ja:トロオドン pt:Troodonte sk:Troodon

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