A newly identified species of prehistoric fish that inhabited Australia’s freshwater lakes and rivers approximately 15 million years ago has been named in honor of a researcher from The Australian National University (ANU), who significantly contributed to its discovery.
Professor Jochen Brocks uncovered several fossils of the ancient fish, designated Ferruaspisbrocksi, at the McGraths Flat fossil site, located near Gulgong in New South Wales (NSW). Expressing gratitude for the recognition, Professor Brocks acknowledged his colleagues at the Australian Museum and the University of Canberra for naming the species after him. He highlighted that this remarkable finding provides crucial insights into the evolutionary history of Australia’s freshwater fish species and ancient ecosystems.
Dr. Matthew McCurry, the lead author of the study and a researcher at the Australian Museum and the University of New South Wales (UNSW) Sydney, emphasized the significance of this discovery in filling a crucial gap in scientific knowledge. Prior to the unearthing of this fossil, there was a lack of definitive evidence regarding the period when this group of fish first arrived in Australia and the manner in which they evolved.
Ferruaspisbrocksi represents the earliest known fossil specimen of the Australian Smelt found in the region. According to Dr. McCurry, the discovery of this 15-million-year-old fossil offers an unprecedented opportunity to analyze the evolution of Australian freshwater fish species and reconstruct ancient aquatic ecosystems. As a member of the Osmeriformes fish family, which includes species such as the Australian Grayling and Australian Smelt, Ferruaspisbrocksi helps clarify the timeline of their presence in Australia and the extent of their evolutionary changes over time.
The well-preserved state of the fossilized fish provides valuable insights into its feeding habits and ecological interactions. The stomach contents of the fossilized specimen indicate a diet predominantly consisting of invertebrates, with small phantom midge larvae being the most frequently consumed prey. Additionally, one of the fossils revealed the presence of a parasite—a juvenile freshwater mussel known as a glochidium—attached to its tail. These mussels use fish as hosts during their early developmental stages, attaching themselves to their gills or tails to facilitate movement through aquatic environments.
Professor Brocks described the discovery of the fossil as a striking revelation, particularly because it was the first vertebrate fossil found among the abundant plant and insect remains at McGraths Flat. He remarked on the fossil’s aesthetic appeal, calling it one of the most exquisite specimens he had encountered at the site.
The species name, Ferruaspisbrocksi, reflects both its scientific significance and the conditions in which it was found. The prefix “Ferru” is derived from the Latin word ferrum, meaning iron, in reference to the iron-rich rock encasing the fossil. The suffix “brocksi” pays tribute to Professor Brocks for his role in its discovery.
Dr. Michael Frese, from the University of Canberra and CSIRO, Australia’s national science agency, highlighted another remarkable aspect of the research—the ability to determine the coloration of the prehistoric fish. Through advanced microscopic analysis, researchers identified melanosomes, the microscopic structures responsible for producing pigmentation. The findings revealed that the fish exhibited a darker dorsal surface, a lighter-colored belly, and two lateral stripes along its sides. The study marks a pioneering use of melanosomes in reconstructing the color patterns of an extinct fish species, expanding the application of this technique beyond previous studies that primarily focused on fossilized feathers.
The McGraths Flat fossil site, where the discovery was made, is among a select few locations in Australia classified as a ‘Lagerstätte’—a site known for its exceptionally well-preserved fossils that retain intricate anatomical details. The fossils found in this area, dating between 11 and 16 million years old, provide a comprehensive view of the region’s prehistoric environment. These findings confirm that the Central Tablelands region once hosted a temperate, wet rainforest teeming with diverse flora and fauna.
The results of this study, which shed new light on the evolutionary history of Australia’s freshwater fish, have been published in The Journal of Vertebrate Paleontology
