It lived around 200 million years ago in what is now southern Africa. It was less than two feet long. It probably weighed less than a cat. It had a parrot-like skull and long, fierce-looking vampire-like fangs. It may have had spines like a porcupine. It walked on two legs. And, researchers now say, it ate plants.
According to Sereno, Pegomastax belongs to a group of tiny dinosaurs known as heterodontosaurs, or "different toothed dinosaurs." Behind the sharp fangs lay other teeth suited for eating plants -- teeth that acted almost as self-sharpening scissors.
Although some researchers have argued that the dwarf dinosaurs may have been carnivorous, Sereno disagrees. "Extensive tooth wear and other evidence suggests that all heterodontosaurids were predominantly or exclusively herbivores." Sereno argues that the fangs may have been used for self defense, fighting for mates, or other purposes -- but not largely for feeding. He likened the fangs of Pegomastax to the fangs of modern-day peccaries and fanged deer, which are plant eaters and foragers. “Pegomastax and kin were the most advanced plant-eaters of their day,” Sereno said, pointing to elements of the jaw structure that later evolved again, millions of years later, in mammals.
The heterodontosaurids were one of the first dinosaur types to spread around the planet. The creatures were present when the supercontinent Pangea was just beginning to separate into northern and southern landmasses.
Heterodontosaurid remains have been found in spots around the world, including southern Africa, the southern coast of England, Argentina, western North America, and China.
Charles reminds Ira when it's time to stop talking, helps wrangle this Web site, and produces segments for the radio program. His favorite stories involve chemistry, inventions, nanotechnology, and shiny things with blinking lights.
The views expressed are those of the author and are not necessarily those of Science Friday.
The Future of the Mind: The Scientific Quest to Understand, Enhance, and Empower the Mind