A 370 million year old fossil fish from the Canowindra Fish Bed in central NSW was named as the NSW State Fossil Emblem in 2015.

Mandageria fairfaxi was a large, air-breathing sarcopterygian (lobe-finned) fish that grew up to 1.7 metres long and had powerful jaws lined with many large fangs. It was the largest fish and the top predator among the eight genera of fish known from the Devonian fauna at the site.

Mandageria fairfaxi - computer generated image

Image caption: A computer-generated image of Mandageria fairfaxi, created by 3D laser scanning of a life-size clay reconstruction of the fossil fish made by Bruce Loomes, Honorary Collection Manager of the Age of Fishes Museum, Canowindra.

Skull, replica and diagrammatic reconstruction of Mandageria

Image caption: Top row: Well preserved skulls of Mandageria (from left to right: dorsal view, cast of articulatory neck bones, and cast of gill arches preserved inside the lower jaw). These indicate that it could move its head like a modern fish, unlike the primitive armoured fish that form most of the fish bed assemblage. Central image: A fibreglass replica of the largest known specimen, seen in ventral view. Bottom image: A diagrammatic reconstruction of Mandageria in lateral profile. Images courtesy of Dr Alex Ritchie.

Fifteen specimens of Mandageria fairfaxi were discovered in 1993 near Canowindra. This site contains a unique faunal assemblage, with eight species and some genera (like Mandageria) known only in NSW.

Mandageria fairfaxi belongs to the tetrapodomorphs, a group including the tetrapods and their immediate ancestors the sarcopterygian fish. In the Late Devonian these vertebrates exhibited the beginnings of the transition of fins to limbs, and from using gills in water to breathing air. The fleshy lobes in the paired pectoral and pelvic fins of Mandageria contained bones equivalent to the limb bones of four-legged land animals. They also developed a functional neck joint that meant they could move their heads – an essential step in the evolutionary transition from fish to tetrapods. Tetrapodomorphs are significant because they are considered to be the ancestors of all land vertebrates, including humans.

The Canowindra site represents a mass grave of thousands of fish trapped in a shrinking lake or billabong. The dead fish were rapidly covered by sediments that preserved them. This ensured that the fossils of these important fish were complete and in excellent condition.

Replica of the discovery bed at CanowindraImage caption: The Canowindra Fish Bed was discovered in 1955 by workers reconstructing a bend in the Canowindra–Gooloogong road (now known as Fish Fossil Drive). A full-size replica of the original discovery slab showing dozens of exceptionally well-preserved fish fossils is on display in the Age of Fishes Museum at Candowindra, the state's only museum dedicated solely to fossils. Visitors can see and touch fossil fish specimens including Mandageria, Cabonnichthys, Gooloogongia, Canowindra, Soederbergia, Bothriolepis, Remigolepis and Groenlandaspis.

Seven buried Mandageria

Image caption: A complete fossil specimen of Mandageria fairfaxi, preserved on a bedding plane at the original discovery site near Canowindra. This specimen is just over 1 m long.
Alex Ritchie in a sea of fish slabs

Image caption: Dr Alex Ritchie with some of the fossil slabs excavated in 1993. About 4000 fish specimens were found.

Acknowledgements

  • Dr Ian Percival, Dr Alex Ritchie, Prof. John Long, Dr Gavin Young.
  • James Fairfax, after whom the fossil is named, is thanked for his generous financial support to the Canowindra project.