Biology and Soil Institute, Far East Branch of Russian Academy of Science, ul. 100-letiya Vladivostoka 159, Vladivostok 690022, Russia

Abstract

Typological implications of cladistics' ideas are discussed in the light of the concept of a hierarchical type and its realizations in types of separate taxa of the same level. Contrary to numerous oppositions of "phylogenetic" and "typological" systematics in Hennig's work, there is no essential differences between two "paradigm" (leaving apart techniques). In typological aspect, Hennig's theory could be considered as a narrow variant of phylogenetic typology that associates the revelation of nested monophyletic groups with the accurate character hierarchy. Types of taxa at every level consist primarily of apomorphic and plesiomorphic states of characters distinguishing taxa of that level, but, among the possible diversity of state combinations, they may occur two taxa with types including only either apomorphies or plesiomorphies. Since such situations are rare in nature, the exclusive orientation of cladistics to apomorphies sharply diminishes the opportunity of the construction of natural system. Nevertheless, the "principle of synapomorphy" retains the sound typological element that provides the leadership of cladistics in comparison with other systematic schools.