A POSSIBLE LATE CAMBRIAN VERTEBRATE FROM AUSTRALIA

THE fossil record of early vertebrates starts with certainty with the dermal armour of agnathan fish from the Early-Middle Ordovician of Aus tralia(1,2). Recent controversial acceptance that conodonts(3) and the fragments called Anatolepis(4,5) may be vertebrate remains(6), extend s their fossil record back to the Late Cambrian. Now a new type of pho sphatic skeleton from Australia shows a three-layered structure that i ndicates vertebrate affinity, but with several unique features not kno wn in other vertebrates. The new evidence challenges the most widely a ccepted current theory for the development of the vertebrate skeleton( 7-11), which assumes the odontode (skin denticle) to be the primitive patterning component. The Australian material provides an alternative model for early vertebrate dermal armour with which to assess the vert ebrate-like hard tissues in conodonts(12,13) and the dermal armour of Anatolepis(4-6,14).