First Teeth Grew on Outside of Body
By JENNIFER VIEGAS - NEWS.DISCOVERY.COM
Added: Fri, 18 Nov 2011 04:31:07 UTC
A new discovery negates the "inside-out" theory of tooth evolution.
New research on Early Devonian fish suggests that the world's first teeth evolved outside of the mouth.
Scales on the exterior of the prehistoric shark-resembling fish appear to have evolved into teeth.
Teeth were retained among most vertebrates and were passed down to multiple species, including humans.
The fictional Cheshire cat's smile seemed to have a life of its own, outside of the cat's body, and now new research suggests the world's first teeth grew outside of the mouth before later moving into the oral cavity.
The study, published in the Journal of Vertebrate Paleontology, supports what is known as the "outside-in" hypothesis of tooth evolution. The first teeth and smile, however, did not belong to a cat, but likely were flashed by small and spiny shark-like fishes.
"The first smile would probably have been a prickly one, with many tiny teeth that looked like pointy cheek scales, and other small tooth-like scales wrapping around the lips onto the outside of the head," co-author Mark Wilson told Discovery News.
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