Formation. Location: The Kimberley, NW Australia. Age: Upper
Devonian, Frasnian. 350 million years. Fig.1. 3D skull of the
placoderm Mcnamaraspis kaprios. Courtesy of Dr.J.Long. The
placoderm fish Mcnamaraspis was approximately 25 cm long and,
like other placoderms, had a bony head shield which was joined
to the 'shark'-like body (Fig. 1). Placoderms were the first
jawed fish. The Mcnamaraspis skull exhibits annular cartilage
preserved in the snout, which has never been observed in other
placoderm specimens. This facilitated the entrance of water over
its olfactory organs and hence its sense of smell was acute.
This, together with the sharp teeth, probably made the fish a
highly successful predator (Fig 2). Fig 2. Reconstruction of the
placoderm Mcnamaraspis kaprios. Courtesy of Dr.J.Long Fig 3. Fig
Fig 3. Front view of an arthrodire placoderm fish. Note the
hard, bony teeth used for grabbing shrimp-like crustaceans. Fig
4. Head plates of the long-snouted placoderm Fallocosteus
turnerae. Courtesy of Dr.J.Long