Ouranosaurus, Spinosaurs, and Dimetrodon the Sailed Reptiles

NOTE:  To get to a printable version of my drawings, just click on the "Free Printable Downloads" button above.  The most recent drawings are at the bottom of the list.  The Ouranosaurus and Dimetrodon drawings are both new.  There are around 300 drawings that you can print.

Ouranosaurus

Ouranosaurus was an unusual dinosaur.  It lived in the mid to late Cretaceous Period in what is now North Africa.  It had a sail on its back... sort of like a Spinosaurus.  However, Ouranosaurs was a herbivore, not a carnivore like Spinosaurus.  Another unusual feature is this Iguanodont dinosaur had a duck bill much like a Hadrosaur or duck billed dinosaur.

Ouranosaurus at the Venice Museum

We saw a skeleton display of this unusual dinosaur at the Venice Museum of Natural History.  Now, maybe most tourists don't go to Venice to see Natural History...but we are retired science teachers!  We went with two smart young men...our teenage grand-nephews.  We all were amazed at the number and quality of the displays at this nice museum.  If you go to Venice, we recommend this museum.

Spinosaurus Fishing

Spinosaurus was a huge Theropod carnivorous dinosaur.  New discoveries in Morocco have shown that it was in fact 55 feet or 17 meters long.  (I reccommend the DVD Bigger Than T. rex)  Spinosaurus probably primarily ate fish.  When the fishing was bad it would look to land based prey.  Both Ouranosaurus and Spinosaurs lived at the same time in the same place.  When fish were rare it is probable that Spinosaurs hunted Ouranosaurs.  The other question is why did both dinosaurs that must have evolved from separate lines both have sails on their backs.  Perhaps cooling and heating in this hot Cretaceous Period were the reasons for both Ouranosaurus and Spinosaurs having sails on their backs.

Dimetrodon of the Permian Period

Note:  I did a little remodling of this Dimetrodon drawing since I first posted it. 

It might just be that also in the hot environment of the Permian Period that having a sail was a good adaptation for cooling off.  You might recall that Dimetrodon... a mammal like reptile that lived way before dinosaurs... also had a sail on its back.  The sail may have been used to warm up by standing at 90 degrees to the sun.  Then to cool down the animal would face directly at or directly away from the sun and a breeze or wind may have helped the sail cool off the blood. Although as a little boy, I had Dimetrodon toy animals that came in my package of toy dinosaurs... Dimetrodon is NOT a dinosaur. Dimetrodon lived in the Permian Period well before the dinosaurs.  .    .  MIlLIONS of years before the dinosaurs.  In fact, the name Dimetrodon means "two length teeth"...because it was the first animal with canine teeth.  It is thought that Dimetrodon may be the ancestor to all of us now living mammals.  Another interesting fact is that one of the primary prey species of Dimetrodon was also sporting a "radiator" sail.  It was called Edaphosaurus.  (Sorry...too tired to draw one right now.  but it was much like Dimetrodon but with a smaller had and blunt plant eater or herbivore teeth.)