Troodon

Our view of Troodon has changed a lot over the years. Scientists have recently reclassified many of the known fossils. Most of what we used to call Troodon is now Stenonychosaurus.

The question remains whether we should still consider Troodon a distinct dinosaur. If so, it lived in the Late Cretaceous Period in what is now North America.

Experts are still debating whether Troodon should be a proper dinosaur name.

The only fossils currently known as Troodon are some teeth. Many scientists think these teeth aren't enough by themselves to justify a separate dinosaur name. It may turn out that they belonged to another dinosaur.

Hopefully future research and more fossil discoveries will clarify whether we should continue to use the name Troodon - and if so, what this dinosaur was really like.

Historically, dinosaur researchers have treated the name Troodon as a 'wastebasket taxon'.

A wastebasket taxon is a scientific term that gets used as a catch-all for all sorts of potentially unrelated things. This includes finds people don't know how else to classify.

This means a lot of fossil remains have been called Troodon over the years, sometimes wrongly.

Modern studies have helped to sort out the confusion. Scientists worked out that many of the bones people had been calling Troodon really belonged to another dinosaur called Stenonychosaurus and possibly some others.

These days, the only remains we still call Troodon fossils are the original teeth found in 1856.

The teeth of Troodon and its relatives are quite unusual.

Although Troodon had serrated teeth like the meat-eating dinosaurs it's related to, its tooth shape is a lot like that of some plant-eating animals.

So, experts think Troodon may have been omnivorous, meaning it ate a mixed diet of both meat and vegetation.

Until recently, scientists said Troodon might have been one of the most intelligent dinosaurs.

This was because of its large braincase. But the skull from this study is now identified as belonging to Stenonychosaurus.

This means we don't really know what Troodon's brain was like.

Troodon wasn't a dromaeosaur - the group popularly called raptors that includes the well-known dinosaur Velociraptor. But it was related.

Many of Troodon's relatives had retractable hooked claws on their feet, a lot like those of the dromaeosaurs. But some experts think they evolved them separately.