CLASSIFICATION of STEGOSTOMA
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 :- STEGOSTOMA ( TIGER SHARK )
Geographical distribution
Stegostoma is abundantly found in the Indian Ocean.
Habit and habitat
Tiger shark is found in open water. It is an active swimmer, predaceous feeding on crabs, fishes and turtles.
GENERAL CHARACTERSTICS OF STEGOSTOMA : TIGER SHARK
- A Commonly called as Tiger shark or Zebra shark because of the handsome and brilliant colouration of dark stripes over yellow ground. Coloured stripes of anterior region are very distinct.
- Body is elongated, laterally compressed and divided into head, trunk and tail measuring 3 to 5 meters in length.
- Head as long as broad, snout reduced.
- Transverse ventral mouth is found under the surface of the head.
- Eyes lateral, without nictitating membrane. Spiracles distinct, present behind the eyes.
- 5 pairs of gill-slits in lateral position.
- Fins are first dorsal fin, second dorsal fin, paired pectoral and pelvic fins, anal fin and caudal fin. Tail heterocercal.
Special features
Tiger shark is viviparous. It is also a nuisance to fisheries because it destroys small fishes. Tiger or Zebra shark is famous for its brilliant colouration and ferocious attack and hence called Tiger shark.
Identification
Since this fish has coloured stripes and above features, hence it is Stegostoma.
