What is Elasmobranch?

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About Elasmobranch

The term elasmobranch refers to the sharks, rays, and skates.
These animals have a skeleton made of cartilage, rather than bone.
The other subclass of cartilaginous fish, the Holocephali, consists of Chimaeras – ratfish (Genus Chimaera) and elephantfish (Genus Callorhynchus).
The main differences between these two subclasses are the structure of their gills and how they grow in the embryo.
- Holocephali has four gill slits with a gill cover (an operculum), while Elasmobranchs have five to seven external gill slits with no gill cover.
Characteristics of Elasmobranchs
- Its skeleton is made of cartilage rather than bone.
- They have five to seven gill openings on each side.
- Rigid dorsal fins (and spines if present)
- Spiracles to aid in breathing
- The upper jaw of elasmobranchs is not fused to their skull.
- Elasmobranchs have several rows of teeth which are continually replaced.
- They don’t have swim bladders, but instead their large livers are full of oil to provide buoyancy.
- They reproduce sexually with internal fertilization and either bear live young or lay eggs.
- Elasmobranch skin is made of tiny, hard, tooth-like placoid scales called denticles.
- These are renowned for their highly tuned senses, which make them incredibly successful in their environment.
Their distribution ranges from nearshore regions to the deep oceanic waters.
Some species are known to travel long distances, hence can be considered as highly migratory. Their stock can be found in more than one Exclusive Economic Zone (EEZ)
They are widely distributed in the Oceans but are most diverse in the tropical and subtropical IndoPacific Ocean.

Q1) What is cartilage?

Cartilage is a strong, flexible connective tissue that protects your joints and bones. It acts as a shock absorber throughout your body. Cartilage at the end of your bones reduces friction and prevents them from rubbing together when you use your joints.

Source: Shark & ray meat consumption no longer restricted to India’s tribal & coastal peoples: Paper