Chondrichthyes

Chondrichthyes (pronounced: kon-drik-thees) is a class of fish that includes the sharks, rays, and skates. The name "Chondrichthyes" is derived from the Greek words "chondros" meaning cartilage and "ichthys" meaning fish, referring to the fact that these fish have skeletons made of cartilage rather than bone.

Etymology

The term "Chondrichthyes" is derived from the Greek words "chondros" (χόνδρος), meaning "cartilage", and "ichthys" (ἰχθύς), meaning "fish". This refers to the unique characteristic of these fish, which have skeletons made entirely of cartilage rather than bone.

Characteristics

Chondrichthyes are characterized by their cartilaginous skeletons, as opposed to the bony skeletons of other fish. They also have several other distinctive features, including placoid scales, also known as dermal denticles, which give their skin a rough texture, and a heterocercal tail, in which the upper lobe is larger than the lower lobe.

Classification

Chondrichthyes are divided into two subclasses: Elasmobranchii, which includes sharks, rays, and skates, and Holocephali, which includes the chimaeras, also known as ghost sharks.

Related Terms

Elasmobranchii: The subclass of Chondrichthyes that includes sharks, rays, and skates.
Holocephali: The subclass of Chondrichthyes that includes the chimaeras or ghost sharks.
Placoid scales: The type of scales found on Chondrichthyes, also known as dermal denticles.
Heterocercal tail: A type of tail found in Chondrichthyes, in which the upper lobe is larger than the lower lobe.