It’s been dubbed a mass extinction of company directors, but the six departures from the board of the Australian Institute of Geoscientists in the past nine weeks have had less explanation than the event that wiped out 90 per cent of life on Earth 252 million years ago.

“For reasons which should become clearer with time, we cannot provide any further details around the root causes of this Permian mass extinction of directors, as we are under legal advice not to do so,” said AIG president Dale Sims, in a message to members last week.