During the Late Permian mass extinction 252 million years ago, the diversity of lifestyles - as defined by habitat, feeding and mobility - at the sea floor remained nearly unchanged, despite the loss of over 90% of marine species. The lack of change in the number of lifestyles could explain why so few novel groups of marine organisms arose after the extinction, suggest the authors of a paper published online this week in Nature Geoscience.

William J. Foster and Richard J. Twitchett assessed the lifestyle of each known genus of organism living globally at the sea floor before and after the mass extinction. They broke lifestyles down into three variables: where in the sediment the organism was living, how they ate, and whether they were attached to the sea floor. They found that only one mode of life - the partly buried, stationary, unattached deposit feeders - was lost during the extinction, and only one novel mode, represented by mobile sea lilies, originated in the aftermath.

In an accompanying News and Views article, Martin Aberhan writes: “The lack of globally vacated ecospace could explain the relatively limited origination of higher taxa and novel lifestyles.”