The Primitive Dipnoan Dental Plate

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Abstract
The study of fossil and extant dipnoan dentitions shows that the shagreen of denticles found in such Devonian genera as Uranolophus and Griphognathus is not primitive for the group, that the ontogeny of the extant Neoceratodus is not a guide to the primitive adult tooth plate, that homology between teeth on dipnoan tooth plates and polyphyodont marginal teeth of other osteichthyans has not been established, and that the Chinese Devonian genus Diabolepis should not be regarded as a dipnoan. We conclude that no convincing argument has been advanced to destroy our contention that the primitive dipnoan plate was a relatively featureless sheet that was added to at the margins by the incorporation of small enamel-covered dentine blisters, and was thickened by resorption of the basal bone and subsequent ingrowth by pleromic dentine.