A worm that lived half a billion years ago preferred turning right
Fossils of Spriggina floundersi provide the earliest evidence of animals favouring one side of the body over the other – a feature of nervous systems that we see in our own right- and left-handedness
Fossils of Spriggina floundersi provide the earliest evidence of animals favouring one side of the body over the other – a feature of nervous systems
Read Full Story at New Scientist →Why This Matters
This discovery challenges long-held assumptions about the origins of bilateral symmetry in animals, pushing the timeline of directional behavior back by hundreds of millions of years. It suggests that the neural wiring enabling handedness may have evolved far earlier than previously thought, reshaping how we understand the development of complex movement and sensory processing in early life forms.
Background Context
For decades, the Ediacaran biota—the enigmatic organisms that thrived before the Cambrian explosion—were dismissed as evolutionary dead ends with little connection to modern animals. Yet recent fossil analyses, including those of Spriggina floundersi, reveal sophisticated body plans that defy simple classification, hinting at a deeper ancestral complexity than paleontologists once imagined.
What Happens Next
Paleobiologists will likely intensify searches for additional asymmetrical traits in Ediacaran fossils, potentially uncovering more examples of directional behavior. If confirmed, this could prompt a reevaluation of how nervous systems first emerged, with implications for studying the evolution of intelligence and movement in deep time.
Bigger Picture
The findings align with a growing recognition that early animal evolution was far more dynamic and varied than once believed, with key adaptations appearing long before the Cambrian radiation. This work underscores how chance fossil discoveries can upend textbook narratives, reminding us that the story of life on Earth is still being written.
