lntraspecific Variation Within the Conodont Polygnathus brevilamina

Intraspecific variation was observed in a study of 177 well preserved specimens of the conodont Polygnathus brevilamina. Variations in the size of platform and in the degree of ornamentation of the platform are illustrated. These variations are present in juvenile specimens. The study indicates that the original definition of Polygnathus brevilamina is too narrow and that a broader concept of speciation is needed if conodont species are to be useable