Class Chondrichthyes: The Chondrichthyes are a group of jawed fishes with a cartilaginous skeleton. Diverse species of fish are included in the class, such as sharks, rays.

• They are marine animals with streamlined body and have cartilaginous endoskeleton. Mouth is located ventrally.
• Notochord is persistent throughout life.
• Gill slits are separate and without operculum (gill cover).
• The skin is tough, containing minute placoid scales.
• Teeth are modified placoid scales which are backwardly directed.
• Their jaws are very powerful.
• These animals are predaceous [shark].
• Due to the absence of air bladder, they have to swim constantly to avoid sinking.
• Heart is two-chambered (one auricle and one ventricle).
• Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon).
• They are cold-blooded (poikilothermous) animals, i.e., they lack the capacity to regulate their body temperature.
• Sexes are separate. In males pelvic fins bear claspers.
• They have internal fertilisation and many of them are viviparous [give birth to young ones].
• Examples: Scoliodon (Dog fish), Pristis (Saw fish), Carchaiodon (Great white shark), Trygon (Sting ray).

Chondrichthyes Examples

Some of the prominent examples of cartilaginous fishes are:

Sharks

• Scoliodon (Dogfish)
• Rhincodon (Whale shark)
• Charcarodon charcharias (The great white shark)

Rays

• Trygon (Stingray)
• Torpedo (Electric ray)
• Narcine bancroftii (Lesser electric ray)
• Manta (Manta ray)

Skates

• Leucoraja erinacea (Little skate)
• Cruriraja andamanica (Andaman leg skate)
• Gurgesiella (Small deepwater skate)

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By Team Learning Mantras