A worm that lived half a billion years ago preferred turning right — SkimNews
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- Scott Evans at the American Museum of Natural History and colleagues analyzed 100 fossil specimens of Spriggina floundersi, a flatworm-like creature collected in South Australia.
- Spriggina floundersi lived 555 million years ago during the Ediacaran Period, predating the Cambrian explosion, and foraged on or close to the seafloor by wriggling.
- Of roughly 50 clearly bent fossils, twice as many are bent to the left as to the right — because specimens are mirror-image impressions of the animals, the worms themselves bent right, the team reports.
- Some specimens showed multiple bends in both directions, suggesting the creatures could move either way but had a rightward preference, mirroring patterns of handedness seen in modern animals.
- The finding pushes the emergence of handedness back from the Cambrian Period (~541 million years ago) to the Ediacaran, indicating an advanced nervous system in early multicellular life.
- Russell Bicknell at Flinders University said the discovery gives "important and interesting information about how these behaviours have evolved and how deeply in time they emerged."
- The study, published in Scientific Reports (DOI: 10.1038/s41598-026-53857-x), suggests foundational traits like movement, bilateral symmetry, and handedness were established in the Ediacaran and built upon during the Cambrian.
Why it matters: The discovery shifts the timeline for the evolution of handedness and advanced nervous system traits back roughly 14 million years before the Cambrian explosion, challenging the view that such complex behaviors originated only after animal life diversified. By showing Ediacaran organisms already displayed functional asymmetry, paleontologists gain a new baseline for when the neurological foundations underpinning modern animal behavior were laid.
Ask SkimNews
