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Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China

Chen, Jun-Yuan and Oliveri, Paola and Gao, Feng and Dornbos, Stephen Q. and Li, Chia-Wei and Bottjer, David J. and Davidson, Eric H. (2002) Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China. Developmental Biology, 248 (1). pp. 182-196. ISSN 0012-1606. doi:10.1006/dbio.2002.0714.

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The evolutionary divergence of cnidarian and bilaterian lineages from their remote metazoan ancestor occurred at an unknown depth in time before the Cambrian, since crown group representatives of each are found in Lower Cambrian fossil assemblages. We report here a variety of putative embryonic, larval, and adult microfossils deriving from Precambrian phosphorite deposits of Southwest China, which may predate the Cambrian radiation by 25–45 million years. These are most probably of cnidarian affinity. Large numbers of fossilized early planula-like larvae were observed under the microscope in sections. Though several forms are represented, the majority display remarkable conformity, which is inconsistent with the alternative that they are artifactual mineral inclusions. Some of these fossils are preserved in such high resolution that individual cells can be discerned. We confirm in detail an earlier report of the presence in the same deposits of tabulates, an extinct crown group anthozoan form. Other sections reveal structures that most closely resemble sections of basal modern corals. A large number of fossils similar to modern hydrozoan gastrulae were also observed. These again displayed great morphological consistency. Though only a single example is available, a microscopic animal remarkably similar to a modern adult hydrozoan is also presented. Taken together, the new observations reported in this paper indicate the existence of a diverse and already differentiated cnidarian fauna, long before the Cambrian evolutionary event. It follows that at least stem group bilaterians must also have been present at this time.

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Additional Information:© 2002 Elsevier Science. Received for publication February 13, 2002. Revised April 29, 2002. Accepted April 29, 2002. Published online June 14, 2002. We are pleased to acknowledge helpful comments from Daphne Fautin of the University of Kansas on some of the specimens: it was she who first alerted us to the possible similarities of some fossils to octocoral stalks and polyps. We are grateful to Mark Martindale of the University of Hawaii for comments on the manuscript, and to Doug Erwin of the Smithsonian Institution for a very careful critical review of an earlier draft. We also thank Hamid Bolouri of the University of Hertfordshire for the statistical interpretation of the data and George Rossman of Caltech for the expert assistance with polarized light microscopy. This research was generously supported by the grants of NSF of China (Grants 40132010 and 990902), the Minister of Science and Technology of China (Grant 20007700), the Foundation of the National Museum of Natural Science, Taiwan, China (to J.C.), and the National Science Council, Taiwan, China (to C.L.). The research was also supported by NASA/Ames Grants NAG2-1368 and NAG2-1541.
Funding AgencyGrant Number
National Science Foundation of China40132010
National Science Foundation of China990902
Minister of Science and Technology of China20007700
Foundation of the National Museum of Natural Science (Taiwan)UNSPECIFIED
National Science Council (Taipei)UNSPECIFIED
Subject Keywords:cnidarian; fossil; Precambrian; embryo
Issue or Number:1
Record Number:CaltechAUTHORS:20160121-071018451
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Official Citation:Jun-Yuan Chen, Paola Oliveri, Feng Gao, Stephen Q. Dornbos, Chia-Wei Li, David J. Bottjer, Eric H. Davidson, Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China, Developmental Biology, Volume 248, Issue 1, 1 August 2002, Pages 182-196, ISSN 0012-1606, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63820
Deposited By: Ruth Sustaita
Deposited On:21 Jan 2016 19:20
Last Modified:10 Nov 2021 23:21

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