freshwater crocodile; Australian freshwater crocodile; Johnston's crocodile
Refers specifically to Crocodylus johnsoni, a freshwater crocodile species native to Australia. The term is a straightforward loanword compound.
The Australian freshwater crocodile is smaller and more docile than the saltwater crocodile.
Loanword compound from English 'Australia' + native Japanese 鰐 (わに, 'crocodile'). The katakana spelling reflects the usual kana preference for this term.