Another Monkey Wrench In Human Evolution
http://news.bbc.co.uk/hi/english/sci/tech/newsid_2118000/2118055.stm
With the requisite ignorant press comment "The newly discovered skull finally puts to rest any idea that there might be a single "missing link" between humans and chimpanzees"
Definitely shows how traits come and go depending on selective pressures and even flukes of genetic drift. Brow ridges seem to have come and gone several times during human evolution and possibly a flat face. Some anthropologists believe brain size may be subject to reducing pressures if food sources become rare due to the brains high energy consumption compared to other organs.
Regards,
Mark