A recent study published in the Journal of Vertebrate Paleontology has unveiled a fascinating discovery in New South Wales, Australia: a 15-million-year-old fish fossil, Ferruaspis brocksi, with intact food in its stomach. The fossil was found earlier this year at the McGraths Flat site when a scientist split a rust-colored rock slab, revealing a nearly complete fish with its stomach contents preserved. This remarkable find offers unprecedented insights into the Miocene ecosystem.

An Unexpected Discovery

The Ferruaspis brocksi fossil was unexpectedly found within a rust-colored rock slab. When researchers at the Australian National University split the rock, they uncovered a two-inch fish specimen that was remarkably well-preserved. Not only were the fish's bones intact, but its soft tissues, pigment cells, and stomach contents were also preserved. This level of preservation is rare for ancient fossils and is attributed to the iron-oxide mineral goethite, which helped lock the tissues in place.

Insights Into the Fish's Appearance and Diet

The exceptional preservation of soft tissues provided a detailed look at the fish's physical characteristics, including its color patterns. Analysis revealed dark pigmentation on the fish's back, a pale belly, and two lateral racing stripes that aid in camouflage. This discovery enhances our understanding of the Miocene ecosystem.

Revealing the Fish's Diet and Ecology

The fish's stomach contents shed light on its diet. Researchers found remains of Chaoborus larvae, insect fragments, and bivalve shells. This discovery is the first fossil evidence of Chaoborus larvae being part of a fish's diet, offering insights into the fish's feeding habits. The presence of a juvenile freshwater mussel attached to the fish's tail fin suggests parasitism, marking the oldest direct evidence of this phenomenon in Australia.

The Role of Iron in Fossil Preservation

The discovery of Ferruaspis brocksi highlights the importance of iron, specifically goethite, in preserving soft tissues over millions of years. Iron deposits prevent bacterial decay, preserving delicate materials like proteins and melanin. The preservation of pigment cells within the fossil allows researchers to study pigment patterns across time, providing valuable insights into ancient ecosystems.

Source: Indian Defence Review