Some writers estimate that the recovery after the Permian Extinction Event was not complete until 30 million years after the P-Tr extinction. This figure has been revised downward somewhat.
Permian–Triassic extinction eventScienceDaily (Dec. 23, 2010) — A major new fossil site in south-west China has filled in a sizeable gap in our understanding of how life on this planet recovered from the greatest mass extinction of all time, according to a paper co-authored by Professor Mike Benton, in the School of Earth Sciences, and published in the Proceedings of the Royal Society B. The work is led by scientists from the Chengdu Geological Center in China.
Some 250 million years ago, at the end of the time known as the Permian, life was all but wiped out during a sustained period of massive volcanic eruption and devastating global warming. Only one in ten species survived, and these formed the basis for the recovery of life in the subsequent time period, called the Triassic. The new fossil site -- at Luoping in Yunnan Province -- provides a new window on that recovery, and indicates that it took about 10 million years for a fully-functioning ecosystem to develop.
"The Luoping site dates from the Middle Triassic and contains one of the most diverse marine fossil records in the world," said Professor Benton. "It has yielded 20,000 fossils of fishes, reptiles, shellfish, shrimps and other seabed creatures. We can tell that we're looking at a fully recovered ecosystem because of the diversity of predators, most notably fish and reptiles. It's a much greater diversity than what we see in the Early Triassic -- and it's close to pre-extinction levels."
New Fossil Site in China Shows Long Recovery of Life from the Largest Extinction in Earth's History