Marks on ancient fossilised bones that were thought to prove humans were using ancient tools 3.4 million years ago could just be crocodile bites, according to new research.
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| Linear marks and pits on a 2.5 million-year-old ungulate leg bone from Bouri, Ethiopia [Credit: PNAS] |
This could transform our understanding of early human evolution - and challenges the idea that early humans were using tools 3.4 million years ago, as previously claimed.
Currently, the claim for the earliest stone-tool-assisted butchery relies on a few isolated marks on two fragmentary bones from a 3.4-million-year-old fossil in in Dikika in Ethiopia.
The marks were found on a long bone from a prehistoric type of antelope and the rib of an animal thought to be similar to a buffalo.
Archaeologists believed the findings proved early humans living long before the emergence of our own branch of the evolutionary tree were using stone tools to cut up meat.
'This claim has been heavily disputed as unequivocal evidence for stone tools does not appear until about 800,000 years later', researchers Dr Yonatan Sahle told MailOnline.
Researchers led by the University of Tubingen analysed these mammal bones along with 40 other fossil samples from 3.4, 4.4 and 2.5 million year old deposits from the broader region in the Awash basin of Afar Rift, Ethiopia.
Previously these bones were said to be signs of early human butchery - specifically filleting and dismembering.
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| Linear marks and pits on a 2.5 million-year-old ungulate leg bone from Bouri, Ethiopia [Credit: PNAS] |
'This is seven years before work on the kind of marks that crocodile teeth leave on the bones of their prey were published', Dr Sahle said.
'Now that we know how similar some crocodile feeding traces are to traces left by stone-tool-assisted butchery, we admit it is impossible to ascertain hominid butchery', he said.
Dr Sahle said it was 'absolutely possible that some were bitten by crocodiles, some trampled, and some even butchered.'
However, differentiating between these activities is extremely difficult.
'Two other claims of similar nature (one that claims hominin occupation of India by 2.6 million years ago, and another of California by 130 thousand years ago) both rely on purported cut and percussion marks on the surface of a few bone assemblages.
'In all of these works, the exceptional claims have not been supported by exceptional evidence - and crocodiles were completely ignored', he said.
For most archaeologists unequivocal evidence for stone tool use comes from several localities at Gona in Ethiopia and at 2.6 million years ago.
In particular, artefacts were found near the remains of one of the earliest Homo fossils, Homo habilis, also known as 'the handy man', and this culture is described as Oldowan.
'This is strong evidence. Could hominids have used tools prior to that? Maybe! We will have to wait for convincing evidence before we change textbooks on this topic', he said.
'We have to collect more samples, conduct more experiments, and move away from inference based on isolated samples and marks in order to better bound equifinality', he said.
The study is published in the Proceedings of the National Academy of Sciences.
Author: Phoebe Weston | Source: Daily Mail [November 08, 2017]
