Two species of crocodile live in Kakadu : the Freshwater Crocodile ( Crocodylus johnstonii ) and the Estuarine , or Saltwater Crocodile ( C. porosus ) . Two species of crocodile occur in Kakadu : the Freshwater Crocodile ( Crocodylus johnstonii ) and the Estuarine , or Saltwater Crocodile ( C. porosus ) .