Question

Presence of claspers is an important character in
(a)Sphyrna
(b)Echeneis
(c)Hippocampus
(d)Exocoetus

Answer 1

Hint: In some fishes, sexual dimorphism is present and these fishes are exclusively restricted to the marine habitat. Also, a spiral valve is present in the intestine to prevent the backflow of food.

Complete answer:
Presence of claspers is an important character in ‘Sphyrna’. This aquatic organism belongs to the Phylum- Chordata and Class- Chondrichthyes. It is a cartilaginous fish. The males can be distinguished from the female, since the male possesses a pair of hard elongated claspers attached to the pelvic fins. The claspers help in copulation. Moreover, claspers are eaten as food by some people. It yields liver oil.

Additional Information:
General features of Chondrichthyes:
These are marine animals possessing streamlined body.Notochord is persistent throughout life. Their endoskeleton is composed of cartilage. Their jaws are powerful and the mouth is located ventrally. Teeth are modified placoid scales which are backwardly directed. Skin is hard containing minute placoid scales. Gill slits are separate and without operculum (gill cover). Exception: Chimaeras
Air bladder which is also known as the swim bladder is absent. Therefore, they have to keep on swimming continuously to avoid sinking. Two-chambered heart is present, having one auricle and one ventricle. These organisms are cold-blooded (poikilothermic organisms). The organisms are predacious. Some possess electric organs like Torpedo and some have poison sting like Trygon. Sexes are separate. In males, claspers are attached to the pelvic fins which are used in copulation. Internal fertilization is there. Many of these organisms are viviparous i.e., give birth to the young ones directly. There are 10 pairs of cranial nerves present.
So, the correct answer is ‘Sphyrna.'

Note:
Poikilothermic organisms are the ones which lack the ability to regulate their body temperature. And these are also referred to as cold-blooded organisms. Sphyrna are also known as hammer headed sharks.