A new study published in the journal Nature suggests that our teeth may be sensitive due to their evolution from a 500-million-year-old fish. The researchers found similarities between the sensory organs of ancient arthropods and early vertebrate fish, including the presence of nerves in the outside teeth of catfish, sharks, and skates.
Scientists have long been puzzled by the origin of teeth, but the study’s lead author, Yara Haridy, was initially looking for fossils of animals with backbones. She analyzed hundreds of vertebrate specimens using a CT scanner and focused on dentin, the inner layer of teeth that sends sensory information to nerves in the pulp.
The researchers discovered a fossil from the Cambrian period called Anatolepis, which had pores underneath its outer armor that could indicate it contained dentin. However, when they compared it to other specimens, they found that the features were similar to those used by modern arthropods for sensing temperature and vibration.
The study suggests that early vertebrates evolved sensory solutions independently of arthropods to cope with their environment. The researchers believe that ancient fish had pointy structures near their mouth that helped them sense the properties of the water, which eventually led to the development of teeth.
The findings may explain why our teeth are sensitive to cold drinks or pain, as they retained a primitive sensory feature from their ancient ancestors.
Source: https://phys.org/news/2025-05-teeth-million-year-fish.html