An elusive new species of great ape, known to locals as the "lion killer", may have been discovered in remote forests of the Congo. The creatures are far larger and more aggressive than normal chimpanzees and have provoked much debate among experts. Some believe that the lion killers are a previously unknown species and should join the other great apes: the chimp, bonobo, gorilla and orang utan. But others say they are unusually aggressive chimps with odd gorilla-like characteristics. Legends of lost apes of the Congo basin go back more than a century and inspired the 1980 novel Congo by...