Question

What is the difference between Chondrichthyes and Osteichthyes?

Answer 1

Chondrichthyes:

A class of fishes that includes fishes with a cartilaginous skeleton.

Osteichthyes:

A class of fishes that includes fishes with a bony skeleton.

Differences between Chondrichthyes and Osteichthyes:

Chondrichthyes	Osteichthyes
They can be exclusively found in marine water.	They can be found in both fresh and marine water.
2. Their body is made up of very small denticles coated with sharp enamel known as placoid.	2. Their exoskeleton is made up of thin bony plates called cycloids.
3. Their mouth is ventral in position.	3. Their mouth is terminal in position.
4. They possess $5-7$ pairs of gills.	4. They possess $4$ pairs of gills.
5. Example- sharks, rays, skates, etc.	5. Example- lungfish, clownfish, etc.