Ancient Fish Fossil Reveals 16 Million Year Old Meal in Australia

Iruni Kalupahana Jadetimes Staff

I. Kalupahana is a Jadetimes news reporter covering Australia

---

Image source: Salty Dingo/Australian Museum

Paleontologists have discovered a beautifully preserved fossil of a previously undescribed species of fish, Ferruaspis brocksi, in central New South Wales, Australia. The find, ranging from 16 million years old and from the Miocene Epoch, at the McGraths Flat site is giving remarkable insights into ancient ecosystems. Goethite, an iron rich mineral, assisted in fossilization, preserving intricate details of the fish, such as stomach content, colouration, and soft tissue.

The significance of the discovery extends to finding a new species. The scientists also recovered the first detailed fossil record of Osmeriformes, a group that includes today's smelts and graylings, within Australia. It had only existed in theory prior to this time that these fish were present in the continent. This fossil carries significant data in their evolutionary background and migration process.

A detailed inspection of the stomach and gut contents of the fish revealed that F. brocksi was an avid feeder on phantom midge larvae, insect wings, and even the occasional small mollusk. These findings are another crucial piece of the puzzle in attempting to reconstruct ancient food webs and ecological associations. The presence of insect larvae suggests that the fish was likely a night time predator, as most Chaoborus species (phantom midges) spend the day resting in sediments to escape predators.

Among the more unusual finds was a freshwater mussel which had become lodged on the tail fin of a fossilized F. brocksi. Given that the lake environment where the fossil was found was not conducive for mussel reproduction, scientists speculate the fish had been parasitized in a nearby river and swam up into the lake. This is valuable evidence for connectivity of ancient waterways.

Dr. Michael Frese, a coauthor of the research and associate professor at the University of Canberra, emphasized the remarkable preservation of fossils at McGraths Flat. He further added that such accurate preservation is rare and offers a unique opportunity to study the coloration and soft tissue of fossilized fish. The study, published in the Journal of Vertebrate Paleontology, highlights how advanced imaging techniques allow scientists to examine even microscopic details of ancient animals.

The find of Ferruaspis brocksi fills out our understanding of the diversity of prehistoric freshwater fish in Australia and their ecological function. Through examining fossils at such a remarkable level of detail, scientists continue to reveal new facets of bygone life, furthering our knowledge of how ecosystems developed over millions of years.