Remains from Chad desert provoke rancorous dispute over whether species was earliest to walk upright

It is a dispute that has taken a long time to reach boiling point. Seven million years after an apelike creature – since nicknamed Toumaï – traversed the landscape of modern Chad, its means of mobility has triggered a dispute among fossil experts. Some claim this was the oldest member of the human lineage. Others that it was just an old ape.

The row, kindled by a paper in Nature, last week led scientists to denounce opponents while others accused rivals of building theories on “less than five minutes’ observation” .