Flinders University researchers have taken a revealing look inside the head of one of the first animals to crawl from the water to live on land more than 380 million years ago.
Using high-tech neutron imaging, they scanned the skull and braincase of the only known specimen of Koharalepis jarviki, a large fossil fish found in freshwater rivers in the vast Lashly Mountains region of Antarctica which lived during the Devonian Period or 'Age of Fishes'.
"This precious fossil belongs to a group called the Canowindridae which highlights the ancient links between Australia and Antarctica," says Flinders University Research Fellow Dr Alice Clement, coauthor of a new article in Frontiers in Ecology and Evolution.
"It is important to study such specimens from the Devonian Age of Fishes when the waters teemed with predatory lobe-finned fish like this that are closely related to land animals (tetrapods)," says Dr Clement, from the College of Science and Engineering.
Koharalepis is a member of the Canowindrid family, a group that lived in East Gondwana and have fossils found today across Australia and Antarctica. It is an ancestor of the first land animals or four-limbed vertebrate tetrapods.
Lead author of the new study, Corinne Mensforth, a PhD candidate from the Flinders Palaeontology Lab, says: "We chose to focus on Koharalepis as it is the only fossil in the entire family to preserve the internal bones of the skull, which gives us valuable insights into its braincase and neuroanatomy."
"We found evidence that the brain of Koharalepis was similar to those of the fishes that straddle 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.
"Koharalepis which grew to about 1 metre was an ambush predator that preyed on other smaller animals in their environment, and with relatively small eyes it must have relied heavily on its other senses to capture its prey."
Another coauthor of the latest study, Flinders University Emeritus Professor John Long, was part of earlier research describing Koharalepis in 1991-92.
Professor Long says the new data generated by modern non-destructive imaging techniques describe the internal skeleton of the skull, shoulder girdle and part of the backbone.
"This has enabled us to understand some of the behaviour, adaptations and relationships of Koharalepis to its environment and to the other tetrapod-like fishes - and how fish first left the water to live on land approximately 385 million years ago," he says.
The article, 'New data on the sarcopterygian Koharalepis jarviki (Tetrapodomorpha; Canowindridae) from the Late Devonian of Antarctica, revealed via synchrotron and neutron tomography' (2026) by Corinne L Mensforth, John A Long, Joseph J Bevitt (Australian Centre for Neutron Scattering, ANSTO) and Alice M Clement has been in Frontiers in Ecology and Evolution. DOI: 10.3389/fevo.2026.1765271.
Acknowledgements: This work was supported by the Australian Research Council (DP 200103398), with thanks to Dr Matthew McCurry (Australian Museum) for specimen loan and Anton Maksimenko for assistance with synchrotron scanning (Australian Nuclear Science and Technology Organisation).
