About 360-70 million years ago in a time known as the Devonian Period, thousands of strange-looking armoured fish perished in a freshwater lake or billabong as it dried up during a severe drought. The whole fish population, adults and juveniles alike, were tightly concentrated in a small area. They were then rapidly covered with sediment that later hardened to rock, preserving them for posterity.
Today that same rock preserves and provides evidence of the mass kill event that took place all those millions of years ago, during what is now known as the 'Age of Fishes'.
Canowindra's unique fossil fish deposit was discovered by chance in 1955, when a council road worker, who was grading an unsealed road between Canowindra and Gooloogong in central west New South Wales, turned over a large rock slab with strange impressions on its under surface. He pushed the slab aside to the fence line, where it was later spotted by a local bee-keeper who recognised its importance and notified the Australian Museum in Sydney. Expert examination of the slab later confirmed it to be one of the most remarkable discoveries of its kind anywhere in the world.
In January 1993, after a 20 year search, an exploratory dig led by Dr Alex Ritchie, palaeontologist at the Australian Museum, rediscovered the source of the 1955 fossil fish slab. In July 1993, with local community support and with earth moving equipment provided by Cabonne Shire Council, Alex Ritchie supervised a 10-day major excavation of this world-class fossil fish site.
The finds exceeded all expectations and some 70-80 tonnes of rock slabs, containing around 4,000 fish specimens were recovered from the Canowindra site. Many thousands of complete fish specimens still remain buried at the original site, awaiting excavation. These could well include other animals new to science and possibly even the skeletal remains of some of the earliest known amphibians, our distant ancestors - an exciting prospect!
Because of the sheer scale of the 1993 discoveries, it was decided to keep all of the new discoveries locally and displayed the most important finds in a unique regional museum near where they were discovered. Canowindra's Age of Fishes Museum illustrates the remarkable story of the time when air breathing fishes with fins evolved into fishes with feet and our distant ancestors first stepped onto land.
LIFE IN THE DEVONIAN
The Age of Fishes
In the Devonian period, some 410-360 million years ago, the eastern coastline of Australia lay much further west than today. An extensive river and lake system covered large parts of the continent, draining into shallow seas. Where Canowindra is today would have been a wide flood plain, dotted with large rivers, lakes and billabongs. It was the 'Age of Fishes', and scientists can now reconstruct the Canowindra story from the abundant fish fossils discovered there.
The Canowindra fauna was dominated by two kinds of strange armoured (or placoderm) fishes, Bothriolepis and Remigolepis, which belong to a long-extinct placoderm group called the antiarchs. A third, less common, armoured fish known as Groenlandaspis belonged to another placoderm group called arthrodires.
Abundant fossil remains of Bothriolepis, Remigolepis and Groenlandaspis have been found in late Devonian rocks in most of the world's now widely scattered super-continents. Such finds support the theory that the earth's continents were once grouped together in the form of a super-continent, PANGAEA, which later split apart into LAURASIA in the Northern Hemisphere and GONDWANA (including Australia) in the Southern Hemisphere.
The largest fishes found at Canowindra belong to the air-breathing, lobe-finned sarcopterygians, which included the ancestors of the first vertebrates to invade dry land, amphibians. The larger sarcopterygians from Canowindra have been named after local towns, councils and localities- Canowindra grossi, Mandageria fairfaxi, Cabonnichthys burnsi and Gooloogongia loomesi.
Completing the faunal list at Canowindra is a small, long-snouted lungfish (or dipnoan), known only from two incomplete specimens. These have been identified as a species of Soederberghia , a Devonian lungfish first discovered in the late 1930s in late Devonian rocks East of Greenland. The species found at Canowindra, Soederberghia simpsoni, provides yet another ancient link between today's widely scattered continents.