Superorder: Archosaurs• a group of diapsid reptiles that first evolved from Archosauriform ancestors .• They are represented today by birds and crocodiles.• are set apart by having socketed teeth• four-chambered hearts
CROCODILIANS• From the Middle Triassic• Include the subtropical and tropical alligators, crocodiles, caimans, and a single species of gavials.• They have survived major upheavals such as the break up of the continents and the ice ages.
Nile crocodile - Crocodylus niloticus Caiman - Caimaninae
Distinctive Features• powerful jaws• protective scales• streamlined body• long tail• eyes and nostrils that are positioned on top of the head• elongated snout
Common Characteristics• They usually lay around in the water motionless.• Their eyes and snouts are the only part of their body that stays above the water.• Crocodilians have sharp teeth for capturing large prey.• semi-aquatic predators
Common Characteristics• They have an extra transparent eyelid on each eye that can be closed to protect their eye when underwater.• They have a flap of skin at the back of their throat that prevents water from seeping in when they attack prey underwater.• They can also close their nostrils and ears in a similar manner to prevent the unwanted influx of water.
CROCODILIANS• Their features have changed very little from those of their prehistoric ancestors, proving that their body form has been highly successful in nature.
Crocodiles Alligators Gavial CaimanShape Slender and Broad and long and slightlyof triangular round narrow moresnout pointedprotrud on the hidden hiddening lower jaw inside a inside afourth socket on the socket ontooth upper jaw the upper jaw