Image caption The dinosaur's fangs are considered unusual for a plant eater

A bizarre dinosaur described as a cross between "a bird, a vampire and a porcupine" has been identified from fossils in South Africa.

The species, which was about the size of a domestic cat, lived between 100 and 200 million years ago.

It had a parrot-like beak with two stabbing canines at the front and tall teeth tucked behind for slicing plants.

Prof Paul Sereno, from the University of Chicago, has published the analysis in the journal Zookeys.

Making the animal seem even more bizarre is its covering of bristles, similar to a porcupine's.

It has been given the scientific name Pegomastax africanus, or "thick jaw from Africa". It is a member of the group of dinosaurs known as heterodontosaurs.

Prof Sereno said: "I describe it as a bird, a vampire and a porcupine." The dinosaur had the weight of a small house cat and stood less than a foot 30 cm (1ft) off of the ground.

He said it was "very rare" that a plant-eater would sport sharp-edged, enlarged canines. Some scientists have argued that consuming meat or at the least insects was a good part of the diet of heterodontosaurs.

But the University of Chicago palaeontologist argues in his paper that competitive sparring and self-defence were more likely roles for the fangs, based on a microscopic examination of teeth from Pegomastax and its kin.

He actually made the discovery of the small-bodied herbivore in 1983. Sereno came across the specimen as a graduate student while doing research in a Harvard University laboratory and intended to write about it immediately.

"I said, 'Whoa!' - I realised it was a new species from the moment I set eyes on it," Prof Sereno said. But he says he grew distracted by other things, and had in mind a more ambitious research project.

"There was always a danger that someone would discover it and write about it, and I would read about it," he said, but added it was all for the best: "Hey, I'm smarter than I was then."