Aim To document the historical development of cladistics and the roles palaeontology and biogeography played in establishing coherent concepts of phylogenetic relationships focusing on some aspects of the contributions of Gareth Nelson.
Conclusions Nelson's reformulation of the threefold parallelism provides a rationale for investigating phylogeny, replacing the central role palaeontology once played with biogeography, adding a spatial dimension to the concept of phylogeny. This approach to phylogeny replaces the old ‘transformationist’ view with the cladistic view, the latter dependent on discovering relationships among taxa. Numerical phylogenetic methods are inherently ‘transformationist’ and have replaced stratigraphy as the key to phylogenetic relationships. Numerical methods in systematics and biogeography are inherently transformational and suffer the same problems as the old palaeontology.