Megapnosaurus, meaning “big dead lizard”, is a genus of theropod dinosaur from the Early Jurassic Period. It was named originally named Syntarsus in 1969, but since that name was taken by a beetle described in 1869, the name was changed to Megapnosaurus. The name is not popular with many paleontologists, but it remains the valid name for this genus. This dinosaur genus has been found in bone beds in Africa and North America. This shows that the dinosaur migrated worldwide during the Early Jurassic period when the continents were joined together forming the mega continent Pangaea. There are differences in the specimens found in Africa and North America that support the migration, adaptation, and evolution theories.
Megapnosaurus was a 10 foot long carnivore that weighed approximately 70 pounds. Based on its jaw structure and teeth, scientists believe this was a scavenger as its jaw was too weak to take down and hold prey. It is thought, however, that these dinosaurs may have hunted in packs, as the bones of 30 individuals were found together in one fossil bed. The study of growth rings in the fossilized remains of this dinosaur suggest that Megapnosaurus had a lifespan of only seven years.