Sereno, a world famous dinosaur fossil hunter, found the 95-million-year-old skull of a 30-foot long meat-eater four years ago dubbed Rugops primus, was two-legged but lacked the huge teeth of a meat-eater like T. Rex, leading scientists to believe "wrinkle face" was a scavenger.

The fossil -- and an older one found in Argentina -- is described in the current issue of the Proceedings of the Royal Society of London. Life-sized models were unveiled at the Garfield Park Conservatory in Chicago.

Sereno says the location of the fossils indicate the existence of a land bridge between Africa and South America some 120 million years ago after a supercontinent, Pangea, broke up and the world's land masses drifted apart.