Human Teeth Evolved From Body Armor of Extinct Species

A new study, published on May 21 in the journal Nature, has revealed surprising information about the origins of human teeth.

Our teeth evolved from the piercing “body armor” of extinct fish, which existed about 465 million years ago. The study explained how sensory tissue found within the exoskeletons of the fish can be tied to the same "genetic toolkit" that comprises human teeth. "This shows us that 'teeth' can also be sensory even when they're not in the mouth," Yara Haridy, the study’s co-author, said in a statement.

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The information came as a surprise to Haridy and her fellow researchers, who initially wanted to find the oldest vertebrate fossil ever recorded. Vertebrate fossils can typically be identified because they contain internal tubules which store dentine, the calcified tissue which is found under the enamel of human teeth. Dentine is also found inside the external bumps on the armor of ancient fishes.

While analyzing the “first fish” species, Anatolepis heintzi, scientists found what appeared to be large pores filled with dentine. They compared the fossil to several ancient and modern animals, but upon further inspection, they found the pores to be more similar to the sensory organs which crabs have on their shells. That means Anatolepis heintzi is an invertebrate arthropod rather than a vertebrate fish.

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Scientists were astonished to discover that fish and ancient arthropods produce the same type of mineralized tissue. They believe that human teeth began evolving into their modern form around 460 million years ago after animals utilized the same "genetic toolkit" to make their teeth.

"Viewed through this evolutionary lens, the fact that teeth in the mouth are extremely sensitive is less of a mystery, and more a reflection of their evolutionary origins within the sensory armor of early vertebrates," the study noted.

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