The skull had been found about 200km (125 miles) from Alice Springs, in the Northern Territory (NT), in 2009.
It was thought to belong to a known reptile of the Baru genus but that has now been updated with new study.
The species is expected to be named in 2022, and there is a Baru exhibition in the NT.
Dr Adam Yates, senior curator of Earth Sciences at the Museum and Art Gallery of the Northern Territory, said the skull was found at the Alcoota fossil site in central Australia.
Dr Yates told the BBC the skull was by far the best specimen of a Baru crocodile yet found.
"It tells us about a new species that we didn't realise was inhabiting central Australia. It's somewhat surprising to imagine that central Australia had rivers to support crocodiles," he said.
"It's one more thread in the tapestry in understanding the way Australian fauna has evolved over time."