550-Million-Year-Old Fossil Shows Earliest Evidence of Right-Handedness

A study published July 9 in Scientific Reports reveals that Spriggina floundersi, a worm-like fossil from the Ediacaran period (538–635 million years ago), shows the earliest known evidence of laterality—a preference for turning right. Researchers analyzed over 100 specimens from Nilpena Ediacara National Park and the South Australia Museum, finding that about two-thirds were curved rightward, indicating a biological preference rather than external forces. This suggests Spriggina had a nervous system capable of directed movement, marking a key evolutionary step. The species, first described in 1958 from the Ediacara Hills in South Australia, is the state fossil of South Australia and one of the oldest bilaterally symmetrical animals. Study co-author Scott Evans of the American Museum of Natural History noted that asymmetry appears once left-right body plans evolve. Experts like Russell Bicknell (Flinders University) and Lidya Tarhan (Yale University) support the findings, with Tarhan noting that uniform curvature from currents would not produce varied shapes. Diego García-Bellido (Adelaide University) praised the cautious interpretation. The work links ancient laterality to modern species like walruses and parrots, suggesting deep evolutionary roots for handedness.