In DepthEvolution

Fossils push back origin of key plant groups millions of years

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Science  21 Dec 2018:
Vol. 362, Issue 6421, pp. 1340
DOI: 10.1126/science.362.6421.1340

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Summary

About 250 million years ago, Earth underwent the worst mass extinction event in its history. Researchers have now unearthed fossils of three plant lineages from before this "great dying" at the end of the Permian period. The discovery, of conifers, seed ferns, and a group of cycadlike plants called Bennettitales, is unexpected and may lead to a revision of plant evolution, because all the lineages were thought to have arisen tens of millions of years later. Their uncovering near the Dead Sea also lends support to a 45-year-old idea about why the tropics tend to have more species than higher latitudes. Dry tropical environments may be "cradles" of evolution.