Chondrichthyes

Chondrichthyes, or cartilaginous fish, are a class of jawed vertebrates that includes sharks, rays, and skates.

Unlike bony fish, their skeletons are made entirely of cartilage, a flexible tissue that is lighter than bone. This lighter skeleton, along with an oily liver, helps them with buoyancy. Most species have placoid scales, which feel like sandpaper and are structurally similar to teeth. They have well-developed jaws and paired fins, which allow for efficient movement and hunting. Chondrichthyes are ectothermic and breathe through gills. Sharks are apex predators in many marine ecosystems, known for their powerful jaws and keen sense of smell. Rays and skates are flattened, bottom-dwelling fish that often use their large pectoral fins to glide through the water. They are a diverse group that plays a crucial role in maintaining the balance of marine food webs.