Flinders University researchers have revealed new details about one of the ancient fish species, closely related to the first animals that eventually made the transition from water to land more than 380 million years ago.
Using advanced neutron imaging technology, scientists examine skull and brain Koharalepis jarwickiiA large predatory fish that lived during the Devonian period, often referred to as the “Age of Fishes”. This fossil was discovered in the Lashley Mountains region of Antarctica and is the only known specimen of its kind.
High-tech imaging unlocks ancient anatomy
The research team used non-destructive scanning methods to peer inside the fossil and study structures that had been hidden for hundreds of millions of years.
“This valuable fossil belongs to a group called Canovindridae that highlights the ancient relationship between Australia and Antarctica,” says Flinders University Research Fellow Dr Alice Clement, co-author of a new paper. Frontiers in Ecology and Evolution.
“It is important to study such specimens of fish from the Devonian era, when the waters were filled with predatory lobe-finned fishes, which are closely related to land animals (tetrapods),” says Dr. Clement of the College of Science and Engineering.
koharalepis Belonged to the canowindrid family, a group of fish that once lived in eastern Gondwana, fossils of which are now found in both Antarctica and Australia. Scientists consider these fish to be close relatives of early four-limbed vertebrates that later evolved into land animals.
Clues of water to land conversion
Lead author Corinne Mansforth, a PhD candidate from the Flinders Paleontology Lab, says the fossil is particularly valuable because it preserves the internal bones of the skull.
“We chose to focus on Coharalepis because it is the only fossil in the entire family to preserve the internal bones of the skull, giving us valuable insight into its braincase and neuroanatomy.”
The scans revealed that the fish’s brain has similarities with species associated with the evolutionary transition from aquatic to terrestrial life.
“We found evidence that the brain of Coharalepis was similar to those of fishes that expanded in the vertebrate water-to-land transition.
“We also found adaptations to life near the surface of the water, including openings in the top of the skull for additional air intake and an organ within the brain that detects light and circadian rhythms.”
Researchers believe that these characteristics may have helped the animal survive in shallow environments where access to oxygen near the water surface was important.
Ancient hunters relied on more than sight
The study also sheds light on how koharalepis He may have behaved in his environment. Growing to about 1 meter in length, the fish was probably an ambush predator that hunted small animals in freshwater systems.
“Coharalepis, which grew to about 1 metre, was an ambush predator that hunted other small animals in its environment, and with relatively small eyes it would have relied heavily on its other senses to catch its prey.”
Emeritus Professor John Long of Flinders University, who participated in the first research described earlier koharalepis In 1992, says that modern imaging technology has made it possible to study the internal structures without damaging the fossil.
“This has helped us understand some of the behaviour, adaptations and relationships between the environment of Coharalepis and other tetrapod-like fishes – and how the fish first left the water to live on land about 385 million years ago,” he says.
The new findings provide another important part in the story of how vertebrates evolved from aquatic creatures into animals capable of living on land.
Study by Corinne L. Mansforth, John A. Long, Joseph J. Bevitt (Australian Center for Neutron Scattering, ANSTO) and Alice M. Clement, “New data on the sarcopterygian Coharalepis jarwicki (Tetrapodomorpha; Canovindridae) from the Late Devonian of Antarctica, revealed through synchrotron and neutron tomography” (2026) Was published in. Frontiers in Ecology and Evolution.
The research was supported by the Australian Research Council (DP 200103398), with additional assistance from Dr Matthew McCurry (Australian Museum) and Anton Maximenko from the Australian Nuclear Science and Technology Organisation.