Fossil algae, dating from 541 million years ago, offer new insights into the plant kingdom’s roots

At left, the external surface of Protocodium sinense. Middle , the view through the outer layer made up of utricles. At right, the central siphons - Paleontologists have identified a new genus and species of algae called  Protocodium sinense  that predates the origin of land plants and modern animals and provides new insight into the early diversification of the plant kingdom. Discovered at a site in China, the 541-million-year-old fossil is the first and oldest green alga from this era to be preserved in three dimensions, enabling the researchers to investigate its internal structure and identify the new specimen with unprecedented accuracy. The study was published this week in  BMC Biology , opening a window into a world of evolutionary puzzles that scientists are just beginning to unravel. " Protocodium  belongs to a known lineage of green algae and has a surprisingly modern architecture, showing that these algae were already well diversified before the end of the Ediacaran period," says co-author  Cédric Aria , a post-doctoral researcher in the University of Toronto's department of ecology and evolutionary biology in the Faculty of Arts & Science who is based at the Royal Ontario Museum (ROM). "Its discovery touches the origin of the entire plant kingdom and puts a familiar name on the organisms that preceded the Cambrian explosion over half a billion years ago, when the world's first modern ecosystems emerged." The newly discovered  Protocodium  fossils were found by a team led by Hong Hua, a geology professor, and post-doctoral researcher Shu Chai - both of Northwest University in Xi'an, China.