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Critics Question Homo Naledi Fossil Find in South Africa

Image: Composite skeleton of Homo naledi.

A composite skeleton of Homo naledi surrounded by some of the hundreds of other fossil elements displayed in Magaliesburg, South Africa. Themba Hadebe / AP

A dramatic fossil find has given South Africa reason to celebrate amid economic gloom, but some experts question its scientific significance.

The discovery, in a cave 30 miles northwest of Johannesburg, is Africa's largest collection of hominin (human and human-related) fossils -- 15 individuals pieced together from over 1,500 fragments.

Homo naledi, which has not been dated, has also stirred excitement because researchers say the hominids seemed to bury their dead -- a trait previously thought to be uniquely human.

Some scientists say the conclusions are hasty.

New Species of Human Relative Discovered in South African Cave 1:10

"In science there is always a gap between the data you have and the interpretations you draw. And in the case of proclaiming a new species the gap is really large," said Christoph Zollikofer of the University of Zurich. Others say the fossils belong to an already-named species.

Read More: Scientists Reveal Homo Naledi, Our 'Unprecedented' Newest Cousin

The University of California's Tim White said from what he had seen, the fossils belonged to Homo erectus, a species discovered in the late 19th century.

"New species should not be created willy-nilly. In order to claim a new species one has to demonstrate that it's different from anything that's ever been known," he said.

Questions have also been raised about the failure to date the find and the theory that the species might have disposed of its dead, which has been proposed as the most plausible scenario for the bones' placing in the cave but is ultimately a guess.

Naledi's lead scientist, Lee Berger of Johannesburg's University of the Witwatersrand, countered that his critics were the ones showing haste.

He said they should not "shoot from the hip based on their pre-conceived ideas but look at these papers and give a thoughtful critique in the peer-reviewed literature."

Read More: Different Species of Human Ancestor Lived Near Lucy, Scientists Say

"We were able to mass the intellectual power and energy of more than 60 scientists ... That logically speeds things up."

Homo naledi: Scientists discover new member of human family tree 0:29

A dozen papers on the finds were submitted to the highly regarded journal "Nature" but were not published there.

"Nature publishes short articles on major discoveries," Berger said. "We attempted to put the 12 in and this was simply too much."

Berger, a jocular American with a flare for showmanship, has seen this kind of academic infighting before. In 1995, he and a colleague proposed the 'Taung child', a famed hominin fossil unearthed in 1924, had been killed by an eagle -- a controversial claim at the time.

A decade later, a study on primate predation by crowned eagles provided Berger with his smoking gun -- the puncture marks in the eye sockets of the modern monkeys matched those in the Taung child's.

Read More: 'Mind Blown': Is Human Ancestor Discovery the Long-Sought Missing Link?