A new dinosaur the size of a house cat and described as a cross between "a bird, a vampire and a porcupine" has been identified in a piece of rock from South Africa.

University of Chicago paleontologist Paul Sereno, who published the findings on Wednesday in the online scientific journal ZooKeys, said in an interview with Reuters he actually made the discovery of the small-bodied herbivore in 1983.

Sereno, whose research involves mapping the dinosaur family tree, said he came upon 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 realized it was a new species from the moment I set eyes on it," 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."

The strange-looking species, which Sereno has named Pegomastax africanus, or "thick jaw from Africa," lived between 100 million and 200 million years ago.

"I describe it as a bird, a vampire and a porcupine," Sereno said. It had the weight of a small house cat and stood less than a foot off of the ground.

It had a thick jaw and a blunt beak with a "heightened tooth that sticks down, dagger-like," Sereno said. He said it would have been part of one of three groups that form the base of the dinosaur tree.