Abstract. A monospecific continuum of populations of the conodont genus Gondolella
occurs in a 23 m thick limestone set at the Anisian/Ladinian boundary in the
southwest margin of the Holy Cross Mts, Poland. The change in distribution of
morphological characteristics of the platform element is gradual and consists
in an increase in contribution of morphologically juvenile stages to the
fossil populations. Purely ecological interpretation of this trend as a
continuous change in population dynamics is refuted. The trend reflects a true
evolution. The other elements of the apparatus of Gondolella do not
undergo any significant changes, except possibly for the pl element (“Enantiognathus”).
Time span separating fossil populations with non-overlapping standard
deviation ranges of diagnostic features sets actually the limit to recognition
of temporal subspecies. This is also the limit to precision of
biostratigraphic zonation based upon temporal taxa. It is here proposed to
introduce a nomenclatorial difference between temporal and geographical (biological)
subspecies by insertion of a dash between specific and subspecific names.