A study led by Prof Luis Buatois from the University of Saskatchewan provides new evidence to understand the development of life at Ediacaran-Cambrian boundary times, about 540 million years ago.
Ichnological record of animal-matground interactions across the transition between Ediacaran, left, and Cambrian, right, periods. Image credit: Luis A. Buatois et al.
“During the Cambrian period the face of our planet changed forever and there are still many unanswered questions,” said Prof Buatois, who is the first author of the paper published in the journal Nature Communications.
“I think that our work is showing that the Cambrian was unique in that it witnessed the appearance of modern group of animals, but at the same time the ecology remained similar to that of the Ediacaran for several million years”.
At Fortune Head in eastern Newfoundland, Canada, Prof Buatois with co-authors studied microbially induced sedimentary structures and Ediacaran-type trace fossils formed during the transition between the Ediacaran and earlier Cambrian periods.
Their findings imply that the disappearance of the Ediacaran biota represents an abrupt evolutionary event that corresponded with the appearance of modern animals, rather than a fading away due to the gradual elimination of conditions appropriate for Ediacaran preservation.
The Cambrian period was a time of dramatic biological and sedimentary changes that ultimately led to the development of our modern world.
Prior to the Cambrian, most marine sediments were covered by microbial mats that were host for the bizarre, soft-bodied creatures of the Ediacaran biota.
One prevalent hypothesis argues that this fauna did not actually go extinct at the beginning of the Cambrian, but instead that conditions for preserving the delicate impressions of Ediacaran soft-bodied organisms disappeared with the arrival of burrowing in the Cambrian, and the loss of elements that were instrumental in their preservation as fossils.
“Discoveries like this are so important because they are at the core of our understanding of early evolutionary breakthroughs,” Prof Buatois said.
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Luis A. Buatois et al. 2014. Ediacaran matground ecology persisted into the earliest Cambrian. Nature Communications 5, article number: 3544; doi: 10.1038/ncomms4544
