Burnett Mary Regional Group

Iconic “living fossil” Australian Lungfish proved to originate from Burnett River

Photo credited to David T. Roberts

Granddad, an Australian lungfish that made international headlines after it was discovered his species lived for more than a century, has helped prove this ecologically, evolutionary and culturally significant species originated right here in the Burnett River.

Iconic “living fossil” Australian Lungfish proved to originate from Burnett River

By Tom Espinoza, Threatened Species Ecologist

Thanks to a major scientific breakthrough, funded by BMRG, recent genetic testing has shown the iconic Australian lungfish, a threatened species of great evolutionary importance, originated in the Burnett River, putting the fish, and the region, into the international spotlight.

Known by Traditional Owners of the region as Dhal’la, Djelleh or Theebine, the lungfish is important to Indigenous Dreamtime culture in Australia and is considered one of the most important discoveries in natural history.

The Australian lungfish (Neoceratodus forsteri) was introduced to the international scientific community on the 18th January 1870 by Dr. Gerard Krefft, then curator of the Australian museum in Sydney.

Providing a rare living portal to human evolutionary pathways, the lungfish has remained unchanged for 160 million years, with fossil records dating back 300 million years, giving it the moniker the “living fossil”.

Named for having a lung, rarely seen in fish, it is able to deal with Australian drought. New molecular methods have consolidated the Australian lungfish as the closest living relative to all land-dwelling tetrapods, making it the first species considered to move from aquatic life to terrestrial life.

Many attempts have been made to collect and study the lungfish in Australia, however many biological secrets remained unanswered.

That all changed recently, thanks to one of the first Australian lungfish to be on public display and possibly the world’s most visited fish, lovingly named Granddad.

In the 1930s, Granddad was collected from the wild in south eastern Queensland, although his specific location was unknown due to a lack of historical records. Granddad was transported to the Chicago Shedd aquarium for the 1933 World’s Fair, living out the remainder of his life in captivity there.

The aquarium estimates some 104 million people visited Granddad, before he was euthanized in 2017 due to ill health. This made Granddad the longest living fish held in captivity. Given he was taken as an adult from the wild, Granddad’s true age was unknown, until now.

A recently developed non-lethal method for ageing lungfish allowed the scientific breakthrough to reveal Granddad’s true age at 109 years.

Ageing lungfish has historically proven difficult. Most fish species are aged using their inner ear bone, known as otoliths, which show layers of growth like rings on a tree, counted to reveal their age. However, this method requires euthanasia of the fish to extract the otolith, so is not recommended for a threatened species.

Additionally, the Australian lungfish does not possess typical otoliths that modern teleosts (ray-finned fish) have, being such an ancient species of lobe-finned fish, sharing ancestors that lived around the time of the dinosaurs.

Atmospheric radiocarbon produced from nuclear weapons testing in the 1950s proved successful for ageing younger fish but was costly and had reduced accuracy for older fish as they weren’t alive before the radioactive carbon spike.

Closely related Lobe-finned lungfish were once widely distributed across the world and in Australia, but they have since contracted, with only one species restricted to the Burnett, Mary and Brisbane rivers in Australia—all the more reason to cherish, sustain and raise awareness of this species worldwide.

With many lungfish in the Burnett Mary region, BMRG continues to work on projects protecting this important species.

Our collaborative work on Australian lungfish and their habitats has involved the CSIRO, Department of Regional Development, Manufacturing and Water (Qld), Seqwater, MRCCC and Griffith University. Projects such as the Mary River Recovery Project, Burnett River Water Quality Project, Paddock to Reef and the Threatened Species Flood Recovery have contributed to improving habitat quality and quantity for Australian lungfish.

We now look forward to working more closely with the Traditional Owners of south-east Queensland to combine Western and Indigenous science for better outcomes for the species and its critical habitats.

For further information, visit https://www.frontiersin.org/articles/10.3389/fenvs.2022.931467/full

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