Megapnosaurus was an agile, carnivorous dinosaur that roamed the Earth during the Early Jurassic period. This extinct genus of coelophysid theropod offers valuable insights into the evolution of early meat-eating dinosaurs. It stands as one of the first well-known theropods from its geological epoch, approximately 188 million years ago.
An Early Apex Predator
Megapnosaurus was a bipedal, carnivorous theropod. It was a lightly built, ground-dwelling predator, measuring 2.2 to 3 meters (7.2 to 10 feet) long. This dinosaur weighed 13 to 32 kilograms (29 to 70 pounds), comparable to an ostrich or a human in height, making it relatively large for its time.
The name “Megapnosaurus” translates to “big dead lizard” or “big dead branch,” derived from Greek roots. This name was chosen by the paleontologists who formally renamed the dinosaur in 2001. The name is believed to reference fossil finds near a tree trunk.
Life in the Early Jurassic
Megapnosaurus possessed a slender build, reflecting its swift and agile nature. Its physical appearance included an S-shaped neck, a long tail for balance, and long hind limbs resembling those of large modern birds like the secretarybird. Its forelimbs were shorter, featuring four digits on each hand, a characteristic differing from many later theropods.
As a carnivore, Megapnosaurus preyed on small vertebrates and insects, using its sharp teeth and clawed hands and feet to capture prey. Fossil evidence, including bonebeds with multiple individuals, suggests these dinosaurs hunted in packs. Studies of its scleral rings, eye structures similar to modern nocturnal birds, indicate it hunted under the cover of darkness.
Fossils of Megapnosaurus have been discovered in Southern Africa, in Zimbabwe and South Africa, and also in North America in Arizona. These Early Jurassic regions were characterized by ancient floodplains and desert-like environments with oases. Megapnosaurus coexisted with the prosauropod Massospondylus and ancient crocodilians.
The Dinosaur with Two Names
The dinosaur now known as Megapnosaurus was originally named Syntarsus by Michael A. Raath in 1969. This name was later found to be already in use for a genus of beetle discovered in 1869, a situation known as “pre-occupied” in scientific nomenclature. Under the International Code of Zoological Nomenclature (ICZN), a scientific name must be unique to prevent confusion.
To resolve this issue, the dinosaur was formally renamed Megapnosaurus by Michael Ivie, Adam Ślipiński, and Piotr Węgrzynowicz in 2001. This renaming generated discussion among paleontologists, partly because the original describer, Raath, was not directly involved. Megapnosaurus remains the accepted name for this Early Jurassic theropod.