The biostratigraphy of Carboniferous chondrichthyans

Among several groups of fishes existing in the Carboniferous, the Chondrichthyes appear to have the greatest stratigraphic potential. However, despite the long history of investigation into Paleozoic sharks, and especially their teeth, our knowledge of their usefulness in biostratigraphy and palaeoecology is still at an early stage of development. This is mainly because for a long time palaeoichthyologists have been focused on descriptions of individual taxa, and not on documenting whole assemblages. The microscopic teeth of pelagic stem-group Chondrichthyes, such as Thrinacodus (Phoebodontiformes), Denaea and Stethacanthulus (Falcatidae, Symmoriiformes) appear to be more useful than macrofossils (e.g. tooth plates of Holocephali) because of their wider geographical distribution and weaker facies dependence.