Ornitholestes – Questions about this Jurassic Theropod

Thanks to episode two of the “Walking with Dinosaurs” television series, we get a lot of questions about Ornitholestes.  Viewers watching the episode entitled “Time of the Titans”, which focuses on life on the Laurasian plain during the Late Jurassic, in what was to become the western United States, come across this small, active dinosaur as it attacks hatching Sauropods.

Unfortunately, as far as we know, there is not a lot of fossil material associated with this particular genus of Late Jurassic meat-eater.  There is one badly crushed skull and some associated bones found that have been ascribed to Ornitholestes and this discovery was more than one hundred years ago.  Since that time, no other fossils relating to this dinosaur have been found.

A little over two metres in length (a third of which was tail), this dinosaur weighed about us much as an Alsatian dog.  The skull indicates that it was a meat-eating; with jaws full of sharp teeth.  The long-hands ended in three fingers which were probably used to grasp its prey – smaller reptiles, insects, mammals and such like.  Palaeontologists have speculated that it probably inhabited forest areas, this would make the preservation of any organic material highly unlikely.  This may explain why fossils of this dinosaur are so rare, despite the plentiful dinosaur material preserved in the Morrison Formation.

A Scale Drawing of Ornitholestes

Picture Credit: Everything Dinosaur

The name of this dinosaur means “bird stealer”, the arms with their clawed hands looked strong enough to snatch a bird from its perch.  In the 1903 scientific description put forward by Henry Fairfield Osborn he stated that this dinosaur probably specialised in hunting birds.  This impression was reinforced by Charles Knight, a famous artist and illustrator of the time.  He created an artwork showing Ornitholestes catching a primitive bird (Archaeopteryx).  This helped “cement” into people’s minds the concept of a dinosaur specialising in hunting such creatures, although Osborn, aware of the lack of fossil bird material from the Morrison Formation later refuted this idea.

The Ornitholestes Charles Knight Sketch

Catching the Bird – “Bird Stealer”

Picture Credit: Wildlife Forum/Charles R. Knight Collection

Sometimes Ornitholestes is depicted as having a small crest on its snout, a number of Theropod dinosaurs sported such crests, however, the very crushed nature of the Ornitholestes skull material has prevented palaeontologists from confirming this – the crest could be a deformed and crushed nasal bone.

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