Family Crocodylidae
   Crocodylinae
   Alligatorinae
   Gavialinae Crocodylia is an order of large reptiles that scientists believe branched off from class Reptilia about 220 million years ago.

• Order CROCODYLIA
  • Suborder: Eusuchia
  • Family: Crocodylidae
    • Subfamily: Crocodylinae
      • American Crocodile Crocodylus acutus
      • Slender-snouted Crocodile Crocodylus cataphractus
      • Orinoco Crocodile Crocodylus intermedius
      • Australian Freshwater Crocodile Crocodylus johnstoni
      • Philippine Crocodile Crocodylus mindorensis
      • Morelet's Crocodile Crocodylus moreletii
      • Nile Crocodile Crocodylus niloticus
      • New Guinea Crocodile Crocodylus novaeguineae
      • Mugger/Marsh Crocodile Crocodylus palustris
      • Estuarine/Saltwater Crocodile Crocodylus porosus
      • Cuban Crocodile Crocodylus rhombifer
      • Siamese Crocodile Crocodylus siamensis
      • Dwarf Crocodile Osteolaemus tetraspis
      • False Gharial/Gavial Tomistoma schlegelii
    • Subfamily: Alligatorinae (alligators and caimans)
      • American Alligator Alligator mississippiensis
      • Chinese Alligator Alligator sinensis
      • Common Caiman Caiman crocodilus
        • Bespectacled Caiman Caiman crocodilus crocodilus
        • Brown Caiman Caiman crocodilus fuscus
        • Rio Apaporis Caiman Caiman crocodilus apaporiensis
        • Yacare Caiman Caiman crocodilus yacare
      • Broad-snouted Caiman Caiman latirostros
      • Cuvier's Smooth-fronted Caiman Paleosuchus palpebrosus
      • Scheider's Smooth-fronted Caiman Paleosuchus trigonuatus
      • Black Caiman Melanosuchus niger
    • Subfamily: Gavialinae (Gavial)
      • Gharial Gavialis gangeticus

Extinct suborders and families

Suborder: Eusuchia (one family living, see above)

• Family: Stomatosuchidae
• Family: Hylaeochampsidae
• Family: Bernissartiidae
• Family: Stomatosuchidae
• Family: Crocodylidae

Suborder: Protosuchia

• Family: Protosuchidae
• Family: Sphenosuchidae

Suborder: Mesosuchia

• Family: Atoposauridae
• Family: Goniopholidae
• Family: Paralligatoridae
• Family: Notosuchidae
• Family: Libycosuchidae
• Family: Sphagesauridae
• Family: Hsisosuchidae
• Family: Teleosauridae
• Family: Pholidosauridae
• Family: Congosauridae

Suborder: Sebecosuchia

• Family: Baurusuchidae
• Family: Sebecidae

Suborder: Thalattosuchia

• Family: Metriorhynchidae

Systems

Circulatory

Crocodiles are the exception among reptiles, they have a 4-chambered heart, but unlike mammals, oxygenated and deoxygenated blood can be mixed when the foramen of Panazzi is open, which bridges both ventricles in the heart. This opening is typically only open during diving, in order to shunt blood away from the lungs.

External links

• http://www.il-st-acad-sci.org/kingdom/rept007.html
• http://www.il-st-acad-sci.org/kingdom/rept007a.html
• Florida's Museum of Natural History's Crocodilians Natural History & Conservation site
• International Crocodile Rescue