Deinonychus and Bennettazhia

Deinonychus and Bennetazhia

Deinonychus was a smaller Theropod dinosaur from the early Creataceous of North America.  It problably hunted in packs and had feathers.  Unlike raptors like Velociraptor or Utahraptor, this dinosaur had a killing claw on the middle toe of each foot and of each hand.  The other later raptors had killing claws on the inside toe of each foot.  Deinonychus lived around 110 million years ago and its fossils have been found in Montana, Wyoming, Utah, and Oklahoma, USA.  

Deinonychus was 11 feet  or 3.4 meters long and weighed over 200 lbs.  That is around 90 kg.   So although I said it was a smaller Theropod, it was not exactly tiny.  It appeared to be sleek with upright posture and clearly was built for speed and killing.  The killing claws on the hands and feet were sickle shaped and obviously deadly.  

The full scientific name is Deinonychus antirrhopus.  The first part of a scientific name for an organism is the Genus name and the second part is the species name.  Deinonychus means killing claw and antirrhopus means counter balance because the great paleontologist John Ostrum figured that the tail stuck out to balance the dinosaur as it walked, ran or stood.  

John Ostrum started the Dinosaur Revolution with his analysis of this Theropod dinosaur.  He pointed out that Deinonychus was not slow and plodding and stupid.  It clearly was fast and agile and intelligent.  The Dinosaur Revolution was continued by his student, the great Robert Bakker.  

The Pterosaur was named Bennettazhia.  It was found in the 1920s by Charles Gilmore.  He thought it was a new species of Pteranodon so he named it Pteranodon oregonensis.  Later, in the late 1980s Chrostopher Bennett determined that it was a type of Azhdarchidae and then a Russian paleontologist, Lev Nesov, named it after Bennett.  

Later CT scans showed that this Pterosaur had the body structure to launch itself off the ground.  This revolutionized our understanding of Pterosaurs.  When I was a boy I learned that Pterosaurs could only glide and had to climb up high to start to fly.  That is now an outdated idea. 

Bennettazhia (oringinally Pteranodon oregonensis) had a wingspan of 13 feet or 4 meters.  So it was not a small animal.  The one in the drawing is clearly in the background and a ways away in the distance.  Its wingspan would have been wider than Deinonychus was long. 

You might have noticed the unusual plants in the Deinonychus and Bennettazhia drawing.  Those odd looking plants were from the Cretaceous Period.  I do not know if they were from the early Cretaceous though.   The animals are both from the same region of Early Cretaceous North America. 

 Deinonychus was related to the earlier dinosaur Microraptor.  Microraptor could fly but Deinonycus clearly could not, however, the connection is strong enough that most paleontologists figure that Deinonychus had feathers.

I also should mention that Deinonychus was found with 3 specimens around an apparently killed prey species that had fought back and killed three of the Deinonychus pack.  The brain cavity was large in Deinonychus and it had forward facing eyes like many modern predators. 

Microraptor flying through the Forest

(This is an older drawing so it is higher up in the list of printable drawings.)
(Printable version of the new drawing are at the bottom of the list under the
Paleontology or All Printables button up at the top of the blog.)

One final note:  I got the idea for this drawing from an excellent drawing by Robert Bakker, done when he was John Ostrum's student.   He did his drawing before we knew about so many Theropod dinosaurs having feathers.  So in his drawing the Deinonychus does not have feathers, but mine does.