There are two different theories about the origin of teeth. One of these theories argues that teeth first appeared in the intraoral region. According to the second theory, teeth were once part of the scales and armor of living things, but later evolved into what they are today.
A fossil of a sawfish such as Ischyrhiza mira, which lived in North America between 65 million and 100 million years ago, could end this discussion. In their study, scientists found findings to support the theory that teeth come from outside.
The first tooth samples may be
Like today’s saw sharks and sawfish, this creature also has spines on its snout that are used to chase predators and find food. The sizes of these structures, also called beak dentition, are different from other spines in their bodies.
Researchers conducted a study to reveal the relationship between beak teeth and scales. In these studies, they also discovered a hard outer cuspid layer. The structure they found was much different from what they expected.
While the scientists said that these tooth-like structures were quite complex, they also stated that the teeth they saw in the ancient sawfish were very similar to the teeth we see in sharks today. The teeth of modern sharks are composed of microcrystals that are aligned on the top and scattered towards the bottom. Thus, they can withstand intense pressure and weight. According to the researchers, these structures fulfill the same function in ancient sawfish.
15450
