The first appearance of tooth-like structures is believed to have occurred in the posterior pharynx of jawless fishes more than 500 million years ago. As jawed vertebrates evolved, teeth developed on oral jaws, contributing to the dominance of gnathostomes (jawed vertebrates) in aquatic and terrestrial environments.
While jawless fish like lampreys possess tooth-like structures, teeth are believed to have first evolved in sharks. Early shark-like teeth have been found in fossils dating back to the Early Devonian period, about 410 million years ago.
These early teeth were not as complex as those found in modern vertebrates but laid the foundation for the diverse and specialized dentitions seen across the animal kingdom.
