Structure and function of the tooth plates of the Devonian lungfish Dipterus valenciennesi from Caithness and the Orkney Islands

WA Museum Records and Supplements | Updated 8 years ago

ABSTRACT – The teeth of the Middle Devonian Dipnoan Dipterus valenciennesi are described from new material from Caithness and the Orkney Islands, Scotland. The biostratigraphy of the Old Red Sandstone in these two areas is described on the basis of new information. The pallial dentine is made up of groups of hard clusters of material. The core dentine in the tooth plates is now understood in terms of the development of individual elements making up the structure of the dentine. The first deposited material is interstitial dentine, and the second is transparent dentine which is deposited from the pulp canals against the interstitial dentine. All the core dentine is perforate. Denteons continue to the tip of the tooth, and dentine tubules run from the pulp canals through the transparent dentine to the pallial dentine. The structure IS not that of petrodentine. The difficulties of using living material for the understanding of dentine in remote structures in time are outlined. The relationships of organisms after the development of new palatal biting in gnathostomes is discussed.