The Ancient Armor of Teeth Reveal Sensitivity to Cold and Pain

A recent study by University of Chicago evolutionary biologist Yara Haridy has shed new light on the evolution of human skeletons. Initially, Haridy aimed to investigate how our skeletal structures came into being, but her research took a surprising turn when she discovered that the sensitivity of our teeth can be traced back to ancient armored fish.

The study’s findings suggest that the anatomy of these flaky exoskeletons resembles the structure of vertebrate teeth and was likely used for sensing. The researchers believe that ancient fish evolved jaws and became more predator-like, which made it advantageous to have pointy structures around their mouths. However, the exact function of these early armored scales remained a mystery.

To answer this question, Haridy analyzed fossilized remains from an ancient arthropod called Anatolepis, which was initially thought to be one of the earliest vertebrates on record. The researchers used powerful X-rays to scan the fossils in detail and found that they were not as complex as expected.

However, when considering alternative explanations for the similarity between these early armored scales and vertebrate teeth, Haridy’s team discovered that ancient fish had nerves in their tooth-like scales. This suggested that the armor of these fish was used to sense the water around them, which is now believed to be connected to our own sensitivity to pain and temperature.

According to paleobiologist Joseph Keating, this discovery explains why we get toothaches and highlights the importance of understanding evolutionary history in addressing rare diseases related to skeletal growth. The study also underscores the significance of considering alternative explanations when investigating complex biological phenomena.

This new research provides a fascinating glimpse into our evolutionary past and highlights the intricate connections between ancient armor, sensation, and human health.

Source: https://www.npr.org/2025/05/24/nx-s1-5409367/armored-fish-human-teeth-cold-pain-evolution