A rare fossil fish scan reveals brain features and adaptations tied to the transition from aquatic to land animals.
Researchers at Flinders University have taken a closer look inside the head of one of the earliest animals to move from water onto land more than 380 million years ago.
Using advanced neutron imaging, the team examined the skull and braincase of the only known specimen of Koharalepis jarviki, a large fossil fish discovered in freshwater deposits in Antarctica’s Lashly Mountains. This species lived during the Devonian Period, often called the “Age of Fishes.”
Canowindridae Fossil Links and Early Tetrapod Evolution
“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 belongs to the Canowindrid family, which lived across East Gondwana, with fossils now found in both Australia and Antarctica. It represents an early relative of the first land animals, the four-limbed vertebrates known as tetrapods.
Braincase Insights, Surface Adaptations, and Predatory Behavior
Lead author Corinne Mensforth, a PhD candidate from the Flinders Palaeontology Lab, explains, “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.”
She continues, “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 meter, 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.”
Research History and Evolutionary Insights
Another coauthor, Flinders University Emeritus Professor John Long, contributed to the original 1992 description of Koharalepis.
Professor Long says modern non-destructive imaging methods have revealed details of the internal skeleton, including parts of the skull, shoulder girdle, and backbone.
“This has enabled us to understand some of the behavior, 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.
Reference: “New data on the sarcopterygian Koharalepis jarviki (Tetrapodomorpha; Canowindridae) from the Late Devonian of Antarctica, revealed via synchrotron and neutron tomography” by Corinne L. Mensforth, John A. Long, Joseph J. Bevitt and Alice M. Clement, 27 March 2026, Frontiers in Ecology and Evolution.
DOI: 10.3389/fevo.2026.1765271
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).
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