A new dinosaur resembling a two-legged porcupine with fangs has been identified by a US palaeontologist.
Pegomastax africanus, meaning "thick jaw from Africa", measured about 60cm in length, had a short, parrot-shaped beak, a pair of stabbing canines with tall teeth tucked in behind, and porcupine-like bristles.
The fossil which held the specimen was chipped out of red rock in southern Africa in the 1960s, before it was found at Harvard University by Professor Paul Sereno, a palaeontologist at the University of Chicago.
Details of the dinosaur's anatomy and lifestyle have been published in the online journal ZooKeys.
Despite its long fanged teeth, Pegomastax was a herbivore.
Dr Sereno said it is "very rare" for a plant-eater to have such sharp-edged, enlarged canines. He argued they were most likely used for self-defence and competitive sparring, based on his examination of wear and chipped enamel on the teeth.
Bristles similar to those of Pegomastax were also recently found in China on another tiny fanged plant-eaters, or heterodontosaur, called Tianyulong.
Dr Sereno said when dwarf-sized heterodontosaurs like Pegomastax lived some 200 million years ago, they would have scampered around in search of suitable plants, looking something like a "nimble, two-legged porcupine".
"Pegomastax and kin were the most advanced plant-eaters of their day," he said.