river prawn vs Palaemon australis

river prawn and Palaemon australis both are nouns.

Word	Noun	Adjective	Verb	Adverb
river prawn	Yes	No	No	No
Palaemon australis	Yes	No	No	No

As nouns, river prawn and Palaemon australis are synonyms defined as:

river prawn and Palaemon australis: large (a foot or more) edible freshwater prawn common in Australian rivers

Other synonyms of river prawn include long-clawed prawn.

river prawn (noun)	Palaemon australis (noun)
large (a foot or more) edible freshwater prawn common in Australian rivers	large (a foot or more) edible freshwater prawn common in Australian rivers
large Australian prawn