The Sun Will Come Out Tomorrow? Maybe Not…
by Brian Switek
The worst mass extinction of all time did far more than nearly denude the planet of life. This vast catastrophe—probably triggered about 252 million years ago by massive eruptions of the Siberian Traps volcanoes—destabilized life on Earth so drastically, according to a new study, that ecological aftershocks continued to hinder the recovery of life on land for millions of years.
Much of what paleontologists understand about the event, known as the end-Permian extinction, and its aftermath they learned from the fossil record of marine organisms. Up to 95% of known species, including the last of the trilobites, disappeared during the extinction. And the plentiful record of fossil fish and invertebrates indicates that ecosystems in the seas required about 5 million to 8 million years during the following Triassic period to regain their previous diversity and complexity. The story on land, however, has been unclear.
Now paleontologist Randall Irmis of the University of Utah and the Utah Museum of Natural History in Salt Lake City and geologist Jessica Whiteside of Brown University propose online today in the Proceedings of the Royal Society B that things were just as tough on dry land as in the seas. Irmis and Whiteside examined fossil vertebrate data sets from southern Africa’s Karoo Basin and the Ural region of Russia. They found that the number of different land-dwelling vertebrate genera dropped during the time interval when the extinction struck. In the post-extinction world, a small cadre of “disaster species” made the most of a bad situation. These survivors, including the “shovel lizard” Lystrosaurus, were hardy species that could make a living under distressed conditions. Such creatures quickly colonized and dominated the environments that had been shaken up by the mass extinction…
(read more: Science NOW) (image: Victor O. Leshyk)
* The dicynodont Lystrosaurus browses on a stand of the lycopsid plant Pleuromeia. These species are two of the “disaster taxa” that proliferated in the wake of the end-Permian mass extinction.