Palaeontology

Trilobites ventured beyond the ocean

Journal name:
Nature
Volume:
505,
Pages:
264–265
Date published:
DOI:
doi:10.1038/505264e
Published online

Contrary to their reputation as denizens of the open ocean, the extinct creatures known as trilobites may have crawled up on to tidal flats.

Fossils found by Gabriela Mángano at Canada's University of Saskatchewan and her colleagues in rock deposits from ancient tidal flats reveal that trilobites took to the land during the Cambrian explosion some 540 million years ago, when the number of animal species increased drastically.

The team discovered the fossils along with fossilized tracks in rocks from the US Appalachian Mountains. The rocks also showed signs of cracks from periodic drying, hinting that they originated in a tidal flat zone.

The finding supports the idea that terrestrial creatures evolved from marine rather than freshwater ancestors. Intertidal zones could have provided food or safe havens for these animals, the researchers suggest.

Geology http://doi.org/qnq (2013)

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