Hair, Feathers, and Scales Came From Shared Ancestor

(Nicolas Di-Poï & Michel C. Milinkovitch)

Reptiles may have more in common with birds and mammals than previously thought. A recent study published in the journal Science Advances argues the three evolved from a common ancestor about 320 million years ago. Researchers learned of the connection by finding primordial tissue structures in reptilian embryos—specifically, a nile crocodile, corn snake, and bearded dragon lizards. These structures, called placodes, had only been found in birds and mammals prior to the study. The common ancestor was likely covered in scale-like structures, scientists believe.

(Nicolas Di-Poï & Michel C. Milinkovitch)

The hair, scales, and feathers which grow from placodes led scientists to categorize the three organisms separately. The absence of placodes in reptiles, combined with lack of fossile records, contributed to the debate regarding how the skin appendages formed. Learn more by reading the study in Science Advances, here.