The evolution of brain size through the end-Permian mass extinction

The genus Lystrosaurus, a mammalian ancestor, is famous for surviving the worst extinction of all, the end-Permian mass extinction. The fossil record chronicles the survival of this genus before, through, and after the extinction, offering a unique opportunity to unravel its survival strategies. Many aspects of Lystrosaurus paleobiology have been studied, except the evolution of its brain size. The brain is an energy expensive organ, which puts a high selective pressure on it when resources become scarce; yet, it is also the seat of cognition, and may help to behaviourally adapt to a rapidly changing environment. As such, brain size may decrease or increase depending on the evolutionary response to mass extinction events. Documenting variations of the brain size in Lystrosaurus through the end-Permian mass extinction will shed new light on the evolutionary response of the central nervous system to high stress conditions, and how these dramatic events have shaped the mammalian brain.