Phylum :- CHORDATA ( Notochord and dorsal tubular nerve cord present and gill-slits present)

Group :- CRANIATA ( Cranium with brain present ).

Subphylum :- VERTEBRATA (Vertebral column present ).

Division :- Gnathostomata ( Jaws and paired appendages present ).

Super class :- PISCES (Paired fins , gills and skin with scales)

Class :-  CHONDRICHTHYES { =ELASMOBRANCHI } (Endoskeleton cartilaginous. Scales usually placoid. spiral valve in intestine ).

Sub-class :- Selachi (Sharks and rays. Gills in seperate clefts. Cloaca present).

Order :- PLEUROTREMATA  { =SQUALI } (Pleuro-sides , trema-opening. gill slits lateral, pectoral fins small.)

Family :- SCYLLIDAE ( Asterospondylus. First dorsal fin without spine)

Genus :- SPHYRNA 

Geographical distribution

Sphyrna is found in all tropical and sub-tropical sea waters and Pacific ocean, primarily in warm coastal waters. 

Habit and habitat

Sphyrna is a common marine fish, adapted for deep sea waters. It is a voracious feeder, active swimmer. It eats small fishes, but because of its attacks on man, it is dreaded as man eater.SPHYRNA : HAMMER-HEADED SHARK


  • Commonly called as hammer-headed shark due to the hammer-shaped head, which is produced into two prominent lateral lobes supported by corresponding cartilaginous outgrowths from post orbital or lateral ethmoidal regions of skull. Eyes containing nictitating membrane are placed a the distal extremities of the lateral lobes.
  • Elongated body measuring 4 to 5 metres is divided into head, trunk and tail. The tail is raised upwards and contains caudal fin with fin rays.
  • Dorsal side is greyish while ventral side is yellowish.
  • First dorsal fin is situated opposite to pelvic fin and second dorsal fin opposite to anal fin. Both fins are devoid of spines. Pectoral fin near gill openings.
  • Mouth crescentic and ventral.
  • 5 pairs of gill-slits and lateral in position. Spiracles are absent. Lateral line distinct.
  • Viviparous, producing about 40 young ones.

Special features

Hammer-headed sharks are closely related to carcharhininae but differ in many cranial characters associated with sphyrnidae cephalic ‘hydrofoil or hammer.


Since this fish has hammer-shaped head and above features, hence it is Sphyrna.

This Post Has 2 Comments

Leave a Reply