Scientists have long debated the origins of teeth. Did they evolve from body scales that migrated into the mouths of ancient vertebrates and became adapted for eating — an idea known as the ‘outside-in’ hypothesis? Or did they evolve independent of scales, originating deep within the oral cavity and ultimately mounting onto the jaws — known as the ‘inside-out’ hypothesis? A new study provides evidence for the ‘outside-in’ hypothesis.
Click here for original story, Sawfish fossils suggest teeth likely evolved from body scales in ancient fish
Source: ScienceDaily