Loch Torridon in Scotland, where the microfossil was discovered. Photo: Stefan Krause, Germany, CC BY-SA 3.0, via Wikimedia Commons.
The billion-year-old fossil of an organism, exquisitely preserved in the Scottish Highlands, reveals features of multicellularity nearly 400 million years before the biological trait emerged in the first animals, according to a new report in the journal Current Biology by an international team of researchers, including Boston College paleobotanist Paul Strother.
The discovery could be the “missing link” in the evolution of animals, according to the team, which included scientists from the University of Sheffield, in the UK. The microfossil, discovered at Loch Torridon, contains two distinct cell types and could be the earliest example of complex multicellularity ever recorded, according to the researchers.
The fossil offers new insight into the transition of single celled organisms to complex, multicellular animals. Modern single-celled holozoa include the most basal living animals and the fossil discovered shows an organism which lies somewhere between single cell and multicellular animals, or metazoa.
“Our findings show that the genetic underpinnings of cell-to-cell cohesion and segregation—the ability for different cells to sort themselves into separate regions within a multicellular mass—existed in unicellular organisms a billion years ago, some 400 million years before such capabilities were incorporated into the first animals,” said Strother, a research professor in the Department of Earth and Environmental Sciences at Boston College.
The fossil’s discovery in an inland lake shifts the focus on the first forms of early life from the ocean to freshwater.