The origin and early evolution of neodermata (platyhelminthes): 1.on the possible turbellarian roots of the group – morphological approach
A comparative analysis of molecular based phylogenies of Platyhelminthes and morphological data is provided. Some widespread mistakes in literature (the confusion of Cercomeromorpha hypothesis by Bychowsky and Cercomorpha hypothesis by Janicki, the inclusion of turbellarians PNUK into the family Genostomatidae, etc) are revealed. Synapomorphies for Neodermata proposed by different authors are critically assessed. The ultrastructure of flame bulbs in Neodermata is shown to be a plesiomorphic character rather than a synapomorphy. The morphological analysis proves that Neodermata evolved from the turbellarians close to the early Neoophora. Only the following synapomorphies of Neodermata do not give rise to doubt: 1) the neodermis; 2) the appearance of ciliated larvae; 3) the collar receptors with dense collar inserted into the membrane at the apical level. Other features may be synapomorphies as well as plesiomorphies as well as homoplasies.
Ключевые слова: Platyhelminthes, “Turbellaria”, Neodermata, phylogeny, synapomorphy, plesiomorphy, molecular phylogeny, comparative morphology.