The Fossil Emblem of Western Australia
In the far north of Western Australia, southeast of Fitzroy Crossing, are the remains of a giant barrier reef that 375 million years ago teemed with life. From shales known as the Gogo Formation, that formed in quiet inter-reef bays, have come exquisitely preserved, three-dimensional skeletons of the fishes that swam in these ancient seas. Preserved as original bone in limestone nodules within the shale, they represent the best preserved early fishes in the world.
One of the major groups of extinct fishes that swam around these ancient reefs is a group known as placoderms. One is Mcnamaraspis kaprios , a fish that in life would have been about 25 centimetres long. Like other placoderms it is characterised by a bony head shield that articulates in a ball-and-socket joint to a trunk shield. In life it possessed a shark-like body, with a single dorsal fin; broad, fleshy paired pectoral and pelvic fins; and an anal fin.
Mcnamaraspis is special in that the fossils have annular cartilage preserved in the snout, the first evidence for this structure in placoderm fishes. This is significant because it would have allowed water to flow between the nasal openings and the mouth, indicating that the fish possessed a well developed sense of smell. This, combined with the sharp, prominent teeth imply that Mcnamaraspis was a voracious predator, probably feeding on the small, shrimp-like crustaceans that abounded in the warm, tropical seas of prehistoric Western Australia.
Mcnamaraspis kaprios was found by Western Australian palaeontologist, Dr John Long in August 1986 and described by him in 1995. The name Mcnamaraspis was a tribute to Dr Ken McNamara of the Western Australian Museum for his extensive research on Western Australian fossils. The Greek ending 'aspis' means shield, so the literal translation is 'McNamara's Shield'. The Greek species name kaprios means boar-like, as the Gogo fish had prominent boar-like tusks on its lower jaws. The common name is derived from the Gogo Formation where the fossils were found, which in turn took its name from Gogo Station in the Kimberley.
The initiative for Western Australia to adopt a fossil emblem and for that emblem to be Mcnamaraspis kaprios came from pupils of a Perth primary school - Sutherland Primary School in Dianella. Following a campaign the school initiated in 1994, a State Fossil Emblem Committee was formed in 1995 to provide advice to the then Minister for the Arts regarding appropriate fossil emblems for Western Australia. Following public consultations and consideration of public submissions, the Gogo fish was recommended to Cabinet as the fossil emblem of Western Australia and was proclaimed on 5 December 1995.
Images for Download
To download any of these images:
- Click on the associated link
- Right click on the image and save to desired location; or
- Alternatively, click on the image and drag directly to desktop
The Gogo Fish
(1920 * 1225 pixels)