Robert T. Paine, PhD, is a zoologist and professor emeritus of the University of Washington, who coined[1] the keystone species concept in order to explain the relationship between Pisaster ochraceus, a species of starfish, and Mytilus californianus, a species of mussel.[2] In his classic 1966 paper, Dr. Robert Paine described such a system in Makah Bay in Washington State.[3] This led to his 1969 paper where he proposed the keystone species concept.[4]