GPS Has Revealed How the Oldest Multicellular Organisms Had Sex

By Diane Kelly on at

The global positioning system (GPS) can keep you from getting lost, manage air traffic, and track the migration of endangered species. And in a new study published today by Nature, it’s helped palaeontologists understand how an organism that’s been extinct for about 540 million years reproduced.

Fractofusus is one of the oldest known multicellular organisms, but its frilly, frond-shaped body looks nothing like any animal, plant, or fungus alive today. Its fossils show no sign of a mouth, gut, reproductive organs, or any way of moving. They come in a mix of sizes, some as small as your finger, others as long as your arm, and are usually found in groups.

When a group of geologists led by University of Cambridge researcher Emily Mitchell used GPS to map the exact positions of individual fossils in a community of Fractofusus killed by volcanic ash–and so preserved, Pompeii-like, in their original positions–they found that the fossils weren’t arranged randomly, the way they would be if each individual had settled out of the water column at different times.

Instead, smaller fossils sat in nested clusters around the largest individuals: the smallestFractofusus around the medium-sized ones, the medium sized ones surrounding the largest ones. Only the largest Fractofusus were arranged randomly in space. The pattern suggests that Fractofusus had two distinct ways to reproduce: each individual could send out plantlike runners to grow clones nearby, and they could also release free-floating babies to drift in the open ocean and (eventually) colonize new locations.

There’s still a lot about Fractofusus’ life history that may always remain a mystery to us, such as how (and what) they ate, or how they reacted to predators. But thanks to a technology we all use every day, we now have a better picture of how some of the very first ocean communities grew.

Image: Group of Fractofusus from Newfoundland by AG Liu