euselachians
Euselachians are a group of ancient cartilaginous fishes that lived during the Early Devonian period, around 416 million years ago. They are considered to be one of the earliest known groups of jawed vertebrates, and are seen as a link between the earlier jawless fishes and the modern cartilaginous fishes.
The name "euselachians" means "true sharks" and is used to distinguish this group from the more primitive
Euselachians were some of the first fish to have a more advanced jaw structure, which allowed them
Several fossil specimens of euselachians have been found in rocks dating back to the Early Devonian period.