New Fossil Site in China Shows Long Recovery of Life from the Largest Extinction in Earth's History
ScienceDaily (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.
An ichthyosaur, a one-meter long fish-eating reptile -- from the new fossil site in China. (Credit: Image courtesy of University of Bristol)
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."
Reinforcing this conclusion is the complexity of the food web, with the bottom of the food chains dominated by species typical of later Triassic marine faunas -- such as crustaceans, fishes and bivalves -- and different from preceding ones.
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Proceedings of the Royal Society B
The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction
Shi-xue Hu1, Qi-yue Zhang1, Zhong-Qiang Chen2, Chang-yong Zhou1, Tao Lü1,
Tao Xie1, Wen Wen1, Jin-yuan Huang1 and Michael J. Benton3,*
+Author Affiliations
1Chengdu Institute of Geology and Mineral Resources, Chengdu 610081, China
2School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
3School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
* Author for correspondence (mike.benton@bristol.ac.uk).
Abstract
The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle–late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the Middle Triassic, Yunnan Province and southwest China shows this final stage of community assembly on the continental shelf. The fossil assemblage is a mixture of marine animals, including abundant lightly sclerotized arthropods, associated with fishes, marine reptiles, bivalves, gastropods, belemnoids, ammonoids, echinoderms, brachiopods, conodonts and foraminifers, as well as plants and rare arthropods from nearby land. In some ways, the Luoping biota rebuilt the framework of the pre-extinction latest Permian marine ecosystem, but it differed too in profound ways. New trophic levels were introduced, most notably among top predators in the form of the diverse marine reptiles that had no evident analogues in the Late Permian. The Luoping biota is one of the most diverse Triassic marine fossil Lagerstätten in the world, providing a new and early window on recovery and radiation of Triassic marine ecosystems some 10 Myr after the end-Permian mass extinction.
end-Permian mass extinction, Triassic recovery, Luoping, China, marine reptiles
Received October 18, 2010.
Accepted November 30, 2010.
This Journal is © 2010 The Royal Society
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