Big Al the Allosaurus with Rhamphorhynchus

Big Al the Allosaurus with Rhamphorhynchus

Big Al is the name given to a sub adult or young adult Allosaurus that was found in Wyoming a few years ago.  This dinosaur was nearly complete.  It had a severely infected toe that probably is what killed him.  The toe bone shows severe deformities from infection after being broken, (probably form a compound fracture).  Big Al has several broken bones in places like his ribs.  It is thought that some of them may have been from trying to attack a long neck Sauropod and others may have been from other Allosaurs.  The toe injury is what was the killer though.   Without being able to run and bring down prey a predator is doomed.  Look closely at his right foot in the drawing and in the below photo and you can see the swollen middle toe.

Big Al's Foot with Infected Toe

This can been seen, along with all of the found Big Al Skeleton at the

 Museum of the Rockies in Bozeman, Montana. 

Allosaurus was one of the top predators of the Jurassic Period.  Most fossilized specimens indicate it was around 30 feet or 9 meters long.  However some found fossils have also found evidence that mature Allosaurus could grow to be 40 feet long.  They were therefore as long as a T. rex, but T. rex and Allosaurus never met, because they lived 90 million years or more apart.  If they HAD faced off I think T. rex's much larger hed and powerful bite would have won the day.  Still, Allosaurus was so successful that we have found many many specimens of them in the rock record.  In fact, one "predator trap" was found at the Cleveland-Lloyd Dinosaur Quarry in Eastern Utah where at least 44 specimens of Allosaurus were found.  They are also of differing ages.  So we know Allosaurus was very successful in the Jurassic Period.

Back when I was teaching Science I used to show a great documentary by BBC about Big All.  It is called Walking With Dinosaurs the Ballad of Big Al Special.  This is an excellent documentary.  It starts with telling the story of Big Al with good pretty realistic animation.  Then it has a second part that explains how they made the movie and how the paleontologists made their conclusions about Big Al's life and injuries.  It is really well done and I highly recommend the documentary.   It helps you see how scientists and especially paleontologists work and use the Scientific Method.  I used to call him a Klutzasaurus.

There are several BBC produced "Walking With..." documentaries and they are all very well done.
I especially like Walking With Dinosaurs, Walking With Monsters, Walking With Prehistoric Beasts.

There is also a Rhamphorynchus in the above drawing.  It is actually a Rhamporhynchoid from North America.  Ramphorynchoids originated in Europe and were the first animals to truly fly. . . other than insects.  During the Jurassic the continents were still pretty close and had just started to divide.  The Europe continent was at the time a series of islands and there was no huge expanse of ocean between those islands and the new North American Continent.  Therefore it makes sense that Rhaphorhynchus and its relatives obviously crossed those smaller seaways to arrive in what is now called North America.