An ancient Australian air-breathing fish from 380 million years ago

An extinct lobe-finned fish, a sleek species with large canines and bony scales from the Middle-Late Devonian period, which lasted for about 380 million years has been discovered in Australia. In the past, when rivers poured over the now-dry land, this predatory aquatic animal flourished in what is now Australia, according to Interesting Engineering. Flinders University palaeontologists have named the recently found fish species Harajicadectes zhumini. The fossilised remains were found over 200 kilometres west of Alice Springs at the Harajica Sandstone Member, a distant fossil location in Australia’s Northern Territory. The scientists estimate that adults of this species reached a maximum size of 40 cm based on the fossilised bones. The recently discovered species is a member of the ancient Tetrapodomorph lineage and has distinctive biological characteristics. Large holes were found in the upper part of the specimen’s skull during examination. “These spiracular structures are thought to facilitate surface air-breathing, with modern-day African bichir fish having similar structures for taking in air at the water’s surface,” said Brian Choo, who led the fossil examination. “This feature appears in multiple Tetrapomodorph lineages at about the same time during the Middle-Late Devonian,” added Choo. The authors point out that several other extinct lobe-finned fish species, such as the Gogonasus from Western Australia, have been found to possess the remarkable biological trait of a huge spiracle. Pickeringius, an unrelated ray-finned fish species from Western Australia that was discovered in 2018, is another example of this feature.