Study Traces 643 Reptiles, Finds Lizards Regained Lost Armor After 320 Million Years
Updated
Updated · Baku.ws · May 23
Study Traces 643 Reptiles, Finds Lizards Regained Lost Armor After 320 Million Years
4 articles · Updated · Baku.ws · May 23
Researchers reconstructed dermal bone evolution across 643 living and fossil reptile species, concluding that lizard osteoderms arose multiple times independently rather than from one armored ancestor.
Monitor lizards produced the study’s biggest surprise: after their ancestors lost bony skin armor, the lineage appears to have regained it after reaching Australia about 20 million years ago.
The team links that reversal to a drier Miocene Australia, where osteoderms may have reduced water loss and added protection in open, arid habitats despite the weight cost to active animals.
That makes monitor lizards the only known lizard lineage to re-acquire osteoderms after losing them, challenging Dollo’s law that complex traits do not re-evolve once gone.
Published in the Biological Journal of the Linnean Society, the work settles a long-running debate over reptile armor origins and points to future research on the genes that can restart bone formation in skin.
How can fossil secrets unlocked by new technology help predict future animal evolution?
If evolution can revive lost armor, what other ancient traits lie dormant in modern animal DNA?
Did different ancient reptiles evolve the same armor, or reactivate a shared 'armor gene'?
Independent Origins of Reptile Osteoderms: Goannas Re-Evolve Bone Armor, Challenging Dollo’s Law
Overview
A groundbreaking study published in May 2026 has transformed our understanding of reptile bone armor, known as osteoderms. By meticulously analyzing 643 living and extinct species, researchers discovered that osteoderms did not originate from a single ancestor, but instead evolved independently multiple times over 320 million years. This challenges the traditional view of a singular armored ancestor and highlights the power of convergent evolution. The study’s findings reveal how different reptile lineages developed similar protective features in response to changing environments, reshaping a centuries-old debate about the origins and evolution of reptilian armor.