[8] Fossil records of this group date back 380 million years, around the time when the higher vertebrate classes were beginning to evolve.

[9] It is one of six extant representatives of the ancient air-breathing Dipnoi (lungfishes) that flourished during the Devonian period (about 413–365 million years ago) and is the outgroup to all other members of this lineage.

The Australian lungfish has also been introduced to the Pine, Caboolture, and Condamine Rivers, but current survival and breeding success are unknown.

[15] The Australian lungfish cannot survive complete desiccation of its habitat, but it can live out of water for several days if the surface of its skin is constantly moist.

Unlike the African species, Protopterus, it does not survive dry seasons by secreting a mucous cocoon and burying itself in the mud.

[17] Australian lungfish are olive-green to dull brown on the back, sides, tail, and fins, and pale yellow to orange on the underside.

[9] The dentition of the lungfish is unusual: two incisors, restricted to the upper jaw, are flat, slightly bent, and denticulated on the hind margin.

The dorsal fin typically reaches to the back of the head in young juveniles, and gradually moves caudally until it only extends to the mid-dorsal region in adults.

They show a gradual change in body form as they develop, but no metamorphosis is externally detectable and no obvious point occurs at which they can be termed adult.

[15] Young lungfish are capable of rapid colour change in response to light, but this ability is gradually lost as the pigment becomes denser.

[15] A distinctive characteristic of the Australian lungfish is the presence of a single dorsal lung, used to supplement the oxygen supply through the gills.

[9] During times of excessive activity, drought, or high temperatures (when water becomes deoxygenated), or when prevailing conditions inhibit normal functioning of the gills, the lungfish can rise to the surface and swallow air into its lung.

[12] More frequent air breathing is correlated with periods of greater activity at night when it uses the lung as a supplementary organ of respiration.

The lung is a single long sac situated above and extending the length of the body cavity, and is formed by a ventral outgrowth of the gut.

Blood capillaries run through this region close enough to the air space in the lung to enable gas exchange.

[28] The sound of the lungfish exhaling air at the surface prior to inhaling a fresh breath has been compared to that made by a small bellows.

[17] After an elaborate courtship, the lungfish spawn in pairs, depositing large adhesive eggs amongst aquatic plants.

[18] Contrary to its South American and African relatives, the Australian lungfish does not make a nest or guard or care for its eggs.

The newly laid egg is hemispherical, delicate, heavily yolked, and enclosed in a single vitelline and triple jelly envelope.

[24] The egg is sticky for a short while until silt and small aquatic organisms have covered it, but long enough for it to become attached to submerged vegetation.

[29] The next phase involves behaviour, similar to "follow-the-leader", during which one fish, the male, shows interest in the female and nudges her with his snout.

This crushing mechanism is coupled with hydraulic transport of the food, achieved by movements of the hyoid apparatus, to position the prey within the oral cavity.

Although the status of the Australian lungfish is secure, it is a protected species under the Queensland Fish and Oyster Act of 1914 and capture in the wild is strictly prohibited.

The lungfish is currently protected from fishing, and collection for education or research purposes requires a permit in Queensland, under the Fisheries Act of 1994, and from the Commonwealth Government.

Barriers to movement and altered flow regimens downstream of dams for irrigation purposes could lead to the disruption of existing population structure and cause even more loss of genetic variation.

[10] Researcher Anne Kemp has documented the decline of lungfish in many reservoirs and river systems due to lack of recruitment caused by dams.

Additionally, large adults could remain common for decades and give no indication of a declining population in the longer term.

The dams would have changed the flow of the rivers, eliminating the slow, shallow areas the fish need for spawning.

At 4 feet long and 40 pounds, the lungfish resides at the California Academy of Sciences' Steinhart Aquarium in San Francisco.

[45] In a 2021 FlyLife article, Karl Brandt proposed the Australian lungfish as the inspiration for Gurangatch, the legendary reptile fish from Gandangara mythology.