Paramecium morphometric analysis and taxonomy

Morphometric analysis of 13 cell attributes in 24 stocks of 6 freshwater Pa ramecium morphospecies (including three sibling species of the P. aurelia c omplex- P. biaurelia, P. tetraurelia and P. pentaurelia) was carried out. T he full morphometric data for the main freshwater Paramecium, P. caudatum, P. multimicronucleatum, P. jenningsi, P. bursaria, P. putrinum were shown f or the first time. The data were compared with the authors morphometric mat erial for the brackishwater species of the genus (25 stocks of Fl calkinsi, P. nephridiatum, P. woodruffi and P. duboscqui) and P. polycaryum with the aim of revising the taxonomy of the genus (the existence of the "putrinum" , "woodruffi" and "aurelia" subgroups and their composition). Morphological characteristics were transformed to numerical coding and relationships amo ng these paramecia are represented as dendrograms and two-dimensional figur es using cluster and multidimensional scaling analysis. According to this a nalysis, the "aurelia" subgroup is a real cluster of species as well as the brackishwater paramecia (the "woodruffi" subgroup without P. polycaryum). P. polycaryum is not grouped with either the "woodruffi" or the "aurelia" s ubgroups. P. bursaria and P. putrinum do not have close morphological simil arity as was previously believed. They are not clustered with each other or with other paramecia. Thus, neither type of previous taxonomy (2 subgroups of Woodruff and 3 subgroups in Paramecium taxonomy of Jankowski) is suppor ted by morphometric analysis.