Ancient Fossil Westlothiana Revealed as Aquatic Animal
New X-ray scans prove the 345-million-year-old creature lived in water rather than on land.
Updated on Oct. 11, 2026 in Geography
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Researchers have discovered that the 345-million-year-old fossil Westlothiana lizziae was an aquatic animal after using advanced X-ray imaging. The findings indicate that claw-like feet likely evolved before creatures fully transitioned to terrestrial life.
Why it matters
This reclassification corrects a long-standing belief that the specimen was an early reptile ancestor. It further suggests that amphibious traits existed earlier in the evolutionary timeline than previously documented.
The study utilized synchrotron scans from the European Synchrotron Radiation Facility to identify internal gills and a fish-like skull. These structures were previously hidden inside the stone slabs where the fossil was discovered in 1984.
The players
European Synchrotron Radiation Facility
This facility in Grenoble, France, provides high-energy X-ray beams used to image internal fossil anatomy.
Nature
This is a prominent weekly international scientific journal that publishes peer-reviewed research across various fields.
The details
By reconstructing the internal skeletal structures of the fossil originally described in 1990, scientists confirmed its aquatic nature. The presence of internal gills and a fish-like mouth provides clear evidence against the prior theory that the animal was an early ancestor to land-dwelling reptiles.
Timeline
345 million years ago: The approximate age of the Westlothiana lizziae fossil.
More than 359 million years ago: The time period when Devonian tracks were formed.
1984: The year the fossil was discovered in Scotland.
1990: The year the fossil was formally described.
September 30, 2026: The research results were published in Nature.
The Big Picture
This discovery shifts the understanding of evolutionary history by proving that certain morphological features, such as claw-like feet, preceded the full transition to land. It updates established figures regarding the timeline of amphibious-to-terrestrial adaptation.
This research provides a more accurate map for scientists tracking the lineage of vertebrates that eventually led to land animals. It demonstrates how modern imaging technology can rewrite established histories without the need to find new physical specimens.
The takeaway
Advanced imaging techniques continue to challenge and refine our understanding of ancient biological timelines. This case highlights how non-invasive technology can permanently alter the classification of historical findings.
Further reading
For more on how geographical features shaped evolution, explore the Geography section.
More information
Read the complete Nature research paper on Westlothiana for additional technical data.
Source note: This article includes information reported by SciTechDaily.
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