Wikipedia on Sahelanthropus tchadensis.
Finder of key hominid fossil disputes 7-million-year dating
Brunet appeared to have scored a knockout blow in February this year, when radiological measurements estimated that the soil where Toumai was found was between 6.8 million and 7.2 million years old.
But the man who discovered Toumai, Alain Beauvilain, of the University of Paris at Nanterre, has now publicly challenged this estimate.
But Beauvilain, a Chadian fossil expert of long standing, says that, contrary to Brunet's assertions that the fossil had been "unearthed," the cranium was found loose on the sand.