The Cambrian Explosion: Burgess Shale Fauna

The Cambrian Explosion of diversity was first identified by workers reviewing the Burgess shale fossils.

It appeared that in 5-10 million years, ancestors of all but two of living phyla came into being. (The two phyla are Bryozoans, whose fossils can only be dated back to the Ordovician era, and a small creature recently discovered growing on lobster lips.)

With current work on rocks in Russia and Namibia that bracket the boundary, soft-bodied ancestors to some of the Burgess shale fauna have been found. Now the 5-10 million year "explosion" has been revised to a 35-40 million year period of rapid diversification.

The painting above shows animals from the Changjieng fossil fossil beds. It is an example of a Burgess shale-type community that is younger than the Burgess shale fossil beds (~510 Ma).

Detail of p painting by D.W. Miller from American Scientist, March-April, 1997. Labels added

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