Toothaches Trace Back to Ancient Fish: New Study Reveals Surprising Origins of Teeth.

Ever wondered why your teeth sting when you sip something cold? A recent study published in Nature proposes that tooth sensitivity could be a legacy from the earliest fish that lived over 500 million years ago. These ancient creatures may have developed tooth-like structures not for eating, but to sense their environment.

The evolution of teeth has puzzled scientists for decades. Researchers now believe the earliest version of teeth were structures known as odontodes—tiny, hard protrusions found on the outer armor of prehistoric fish. Unlike modern teeth that form inside the mouth, these odontodes covered the skin and may have served a completely different purpose.

To this day, sharks, stingrays, and catfish are covered in these microscopic tooth-like features, giving their skin a rough, sandpaper-like texture. Theories have long circulated about why odontodes first appeared—some suggest they offered protection from predators, enhanced movement through water, or stored essential minerals. However, the latest findings support another idea: these structures likely served as sensory organs, transmitting environmental cues through nerves.

The study’s lead author, Yara Haridy, a postdoctoral researcher at the University of Chicago, did not initially set out to study teeth. She was investigating what might be the earliest fossil of a vertebrate animal. To explore this question, she requested tiny fossil samples from museums across the U.S., analyzing them with advanced CT scanning techniques.

Haridy zeroed in on dentin, the sensitive tissue inside modern teeth that sends pain signals to nerves. One fossil, Anatolepis, dating back to the Cambrian period, stood out. Its exoskeleton showed tubule-like pores beneath its odontodes—evidence they may have once contained dentin. This insight supports the theory that Anatolepis could be one of the earliest known fish.

Study co-author Neil Shubin noted that these primitive animals lived in highly competitive, predator-rich environments. “Sensing the water around them would have been vital for survival,” he said.

As fish evolved, so did their features. Haridy explained that the development of jaws made it useful to have sharp structures near the mouth. Over time, these pointy odontodes migrated inward, eventually becoming the teeth we have today.

In essence, that nagging toothache might not just be a dental issue—it’s a remnant of a sensory system that helped our ancient aquatic ancestors navigate their world.

Source:https://phys.org/news/2025-05-teeth-million-year-fish.html

This is non-financial/medical advice and made using AI so could be wrong.