Zoology Database

"Zoology Database" provide previous years' question papers for B.Sc zoology students. Last year's M.Sc zoology/ Lifesciences entrance paper is also available here.

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Scientific Name: Crocodylus



Classification


Phylum: Chordata - Dorsal tubular nerve cord, notochord and gill slits present.


Subphylum: Vertebrata - Vertebral column present.


Superclass: Gnathostoma -Jaws and paired appendages present.


Class: Reptilia -Scaly vertebrates. Right and left aortic arches present. Single condyle. Pulmonary respiration. Embryo with amnion and allantois.


Subclass: Archosauria


Order: Crocodilia -Body and head large. Jaws powerful. Skin thick and leathery. Tongue nonprotrusible. Heart 4-chambered.


Suborder: Ophidia -Snakes. Limbs, feet, ear openings sternum and urinary bladder absent. Mandibles jointed anteriorly by ligament. Tongue slender, bifid and protrusible. Left lung reduced.


Genus: Crocodylus


Habit and habitat: It is found in rivers and lakes. The animal makes 10 to 13 metres long tunnel below the level of water. The opening of the tunnel is used as entrance and the other side is used to deposit the eggs.


Characteristics

  1. The body is stout, elongated, 4 to 6 metres in length and divided into head, neck, trunk and tail.
  2. Surface covered by leathery armour of osteoscutes bony scutes arranged in transverse rows.
  3. The upper part of the body is dark olive brown with black spots or bends.
  4. Head long and triangular and narrows towards snout which is not differentiated from the rest of the skull. Jaws long, powerful, rimmed with numerous bluntly conical and unequal teeth, dental formula 16-19/14-15. The first tooth fits into a pit and the fifth mandibular tooth into a notch on the outer side of the upper jaw.
  5. The ear opening small and protected by a small flap of skin.

Videos



References

  • Wikipedia
  • The life of invertebrates by J.Z Young

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