I couldn't find anything either but I thought this article and photo was interesting.
The Marine Corps temporarily had six four-star generals in 2013 — which had never happened before and is unlikely to happen again any time soon. The generals posed for photos in the Home of the Commandants in Washington, D.C., April 19, 2013. From left to right: John Kelly, James Mattis, Joseph Dunford, James Amos, John Allen, and John Paxton Jr.
https:// news.usni.org/2015/05/06/who-will-follow-dunford-as-next-marine-corps-commandant