Overview
- The peer-reviewed study published July 9, 2026, in Scientific Reports analyzed more than 100 Spriggina floundersi fossils from Nilpena and museum collections and reports a statistically significant bias of about two leftward impressions for every rightward one.
- Because the fossils are mirror-image impressions, leftward bends in the rock correspond to the animals bending to the right in life, which the authors interpret as a population-level preference for rightward turns.
- The team measured bend angles, specimen orientations, and bed contexts and rejected simple taphonomic explanations such as uniform current alignment or post-mortem drying because bends varied across slabs and orientations were not consistent.
- From those patterns the authors argue Spriggina was motile and had coordinated sensory–muscular control, a behavioral inference that implies a relatively complex nervous system but remains indirect and debated by specialists.
- The finding pushes evidence for left-right behavioral asymmetry back into the Ediacaran period and underscores Nilpena’s value for snapshots of early animal life while leaving questions about the exact neural anatomy and evolutionary drivers for handedness open for future work.