in other biological disciplines, in protozoology the field of phylogen
etically oriented systematics is currently experiencing a Vital popula
rity. This is not only caused by the discovery of new species with att
ributes or features of missing links or by the elaboration of ultrastr
uctural and molecular features of little-known protozoa during the las
t 20 years, but mainly by the recent establishment of new quantitative
approaches and methods of classification and of phylogeny reconstruct
ion. Among them, the concepts of cladistic taxonomy appear most notabl
e. They allow us to differentiate between homologous characters develo
ped in different historical horizons and to evaluate their impact on t
he development of new strategies.