Late Devonian and Early Carboniferous chondrichthyans from the Fairfield Group, Canning Basin, Western Australia

Abstract

Little is known of the sharks that inhabited latest Devonian and Early Carboniferous environments of the Canning Basin in north-western Australia. This work details a diverse shark fauna from a shallow water environment during an important time in the evolution of vertebrates. This period saw the extinction of numerous jawless and jawed vertebrates at the end of the Late Devonian, followed by an increase in shark diversity in the Carboniferous. Detailed taxonomic analyses of 18 shark taxa in this work have revealed 12 previously undescribed taxa and extended the geographic range of sharks previously described from North Gondwana and southern Laurentia. The widespread occurrence of many sharks has allowed for a relationship between certain genera, and the environment in which they inhabited, to be established. This relationship, described for the Late Devonian, is shown to also be applicable in the Carboniferous shallow water environments of the Canning Basin. This work provides an important data set for understanding changes in vertebrate populations over major extinction events at the end of the Devonian. In addition, the location of the Canning Basin between major faunal provinces, aids in understanding the movements of shark species and faunal exchanges between Late Devonian and Early Carboniferous terranes.