Ancient Fossil Reclassified as Amphibian
A new study reveals that Westlothiana lizziae is an amphibian, not the earliest known land-adapted reptile.
Updated on Sept. 30, 2026 in Reptiles
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Researchers have determined that the 345-million-year-old Westlothiana lizziae fossil is an amphibian rather than an early reptile. X-ray imaging revealed internal gills and fish-like teeth, contradicting its previous classification.
Why it matters
The reclassification suggests that clawed fossil trackways do not reliably indicate the presence of amniotes. This finding forces scientists to rethink the early evolutionary timeline of land-dwelling vertebrates.
The specimen, discovered in 1984, features five-toed feet and claw-like phalanges. It was mistakenly considered an early reptile for over 30 years.
The players
European Synchrotron
This facility provided the high-energy beamline technology necessary to perform non-destructive x-ray scans of the fossil.
University of Oxford
This institution served as a lead research center for the paleontological study.
American Museum of Natural History
This organization collaborated as a lead research institution in the reclassification project.
The details
Using x-ray tomography at the European Synchrotron, researchers reconstructed the creature's internal anatomy. The presence of ossified gills and specific dental structures definitively distinguishes the animal from true amniotes.
Timeline
The fossil was originally discovered in 1984.
The animal lived approximately 345 million years ago.
The research study was published on September 30, 2026.
Deeper Dive
This finding marks a major departure from the long-standing consensus regarding the historical classification of Westlothiana lizziae as the earliest amniote. By invalidating this marker, the study updates a foundational figure previously established by evolutionary biology researchers.
This news provides enthusiasts with a more accurate understanding of prehistoric life and the limitations of fossil trackway interpretations. It highlights how modern imaging technology can fundamentally alter long-held scientific facts.
The takeaway
Scientific understanding of the past is constantly evolving as new technology allows for deeper inspection of existing specimens. This case demonstrates that anatomical details, such as gills, can outweigh external physical traits like clawed feet when defining a species.
Further reading
Learn more about evolutionary history in the Reptiles section.
More information
Read the complete Nature study on Westlothiana evolution.
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