"With no new data, no new ideas, no new methods, no new hypothesis, no new experiments, no new fossils, not even a new classification, this paper will leave everybody wondering what's happened to the peer review process at Nature," White says.
Others welcome Wood and Harrison's warning. An upright stance and other features once considered hominid signatures evolved independently in many ancient primates, remarks anthropologist Tracy Kivell of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Parallel evolution of these traits makes the evolutionary status of proposed early hominids "more uncertain than originally described," Kivell says.
Scientists currently have no good way, either with bones or genes, to test the hypothesis that proposed early hominids are ancestors as advertised, remarks anthropologist John Hawks of the University of Wisconsin–Madison.
Wood and Harrison discuss two cautionary tales of hominid classification gone awry. In one case from more than 30 years ago, scientists thought that 12-million-year-old Asian fossils from a creature called Ramapithecus belonged to a hominid until further finds pegged it as an orangutan ancestor.