A new species of fish that lived in Australian freshwater lakes and rivers about 15 million years ago has been named after the ANU researcher who played a key role in its discovery.


Prof Jochen Brocks discovered several fossils of the ancient fish, named Ferruaspis brocksi, at the McGraths Flat fossil site near Gulgong in NSW.

“This discovery opens new avenues for understanding the evolutionary history of Australia’s freshwater fish species and ancient ecosystems,” Prof Brocks said.

“This little fish is one of the most beautiful fossils I’ve found at McGrath Flat, and finding the first vertebrate among the abundant plant and insect fossils was a real surprise.”

Study lead author Dr Matthew McCurry, from the Australian Museum and UNSW Sydney, said that before this fossil discovery, scientists lacked concrete evidence to pinpoint when this group of fish arrived in Australia and how they evolved over time.

“Ferruaspis brocksi is the first fossil freshwater Australian Smelt to be found in Australia,” Dr McCurry said.

“The discovery of the 15 million-year-old freshwater fish fossil offers us an unprecedented opportunity to understand Australia’s ancient ecosystems and the evolution of its fish species.

“This fossil is part of the Osmeriforms fish family – a diverse group of fish species within Australia that includes species like the Australian Grayling and the Australian Smelt. But, without fossils it has been hard for us to tell exactly when the group arrived in Australia and whether they changed at all through time.”

The researchers said the stomach contents of the fossilised fish is “so well preserved”, scientists now have a glimpse into the behaviour of these ancient species.

“We now know that Ferruaspis brocksi fed on a range of invertebrates, but the most common prey was small phantom midge larvae. One of the fossils even shows a parasite attached to the tail of the fish,” Dr McCurry said.

“It’s a juvenile freshwater mussel called a glochidium. These juvenile mussels attach themselves to the gills or tails of fish to hitch rides up and down streams,” Dr McCurry said.

Professor Brocks added: “This little fish is one of the most beautiful fossils I’ve found at McGrath Flat, and finding the first vertebrate among the abundant plant and insect fossils was a real surprise.”

The species was named Ferruaspis brocksi because it was found encased in iron-rich rock. “Ferru”, from ferrum (Latin) meaning iron, and “brocksi” after Prof Brocks.