Spriggina Fossils Show 550 Million-Year-Old Animal Favored Right Turns, Earliest Known Headed Species
Updated
Updated · KSL.com · Jul 12
Spriggina Fossils Show 550 Million-Year-Old Animal Favored Right Turns, Earliest Known Headed Species
3 articles · Updated · KSL.com · Jul 12
Summary
More than 100 Spriggina fossils indicate the 550 million-year-old animal wriggled across the seafloor and preferentially bent to its right, making it the earliest known example of behavioral handedness.
A roughly 2-to-1 excess of fossils curving left in rock implies right-side bending in life, a statistically significant pattern researchers say points to a directional movement preference.
Different orientations and bend angles across fossil beds, including layers marked by currents, argue against waves, storms or drying as the cause and support active movement.
The study also reinforces Spriggina as the earliest known animal with a head and suggests it already had a nervous system linked to muscles, pushing key animal traits deep into the Ediacaran.
How can a fossil 'snapshot' reveal an ancient worm’s favorite direction, challenging our understanding of early animal intelligence?
If a 550-million-year-old worm was 'right-handed,' are the origins of our own brains far more ancient than we believed?
Earliest Evidence of Behavioral Handedness: Right-Side Preference in Spriggina 550 Million Years Ago
Overview
In 2026, scientists made a groundbreaking discovery by uncovering the earliest evidence of behavioral 'handedness' in the animal kingdom, dating back about 550 million years to the Ediacaran Period. This finding centers on the ancient organism Spriggina floundersi, whose fossils were found in South Australia. Careful research revealed that Spriggina showed a strong right-side preference, a trait similar to what is seen in many modern animals. The exceptional fossil record from the Flinders Ranges helped scientists identify this pattern, showing that behavioral asymmetry has deep evolutionary roots.