The California spiny lobster, or "Panulirus interruptus", is another example of a keystone predator that has a distinct role in maintaining species diversity in its habitat. Robles (1987) demonstrated experimentally that the exclusion of spiny lobsters from the intertidal zone habitats led to the competitive dominance of mussels ("Mytilus edulis" and "M. californianus"). This results shows another example of how the ecological extinction of a keystone predator can reduce species diversity in an ecosystem. Unfortunately, the threshold of ecological extinction has long passed due to over fishing now that many local extinctions of the California spiny lobster are common.