The term "σχιστοσπόνδυλων" refers to a group of animals known as chondrichthyans, which includes sharks, rays, and skates. These creatures are characterized by their cartilaginous skeletons, which are lighter and more flexible than the bony skeletons found in most other fish. They are primarily found in marine environments and play important roles in their ecosystems as predators. Chondrichthyans have unique adaptations, such as electroreception, which allows them to detect electrical fields produced by other animals. They also possess multiple rows of teeth that are continuously replaced throughout their lives. This group of animals is vital for maintaining the balance of marine life and is of significant interest in scientific research.