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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 7423

Peter Eigner; Evolution of Morphologenetic Processes in the Orthoamphisiellidae N. Fam., Oxytrichidae, and Parakahliellidae N. Fam., and Their Depiction Using a Computer Method (Ciliophora, Hypotrichida). J.Eukaryot.Microbiol. 44(6):553-573, 1997

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Forty detailed descriptions of divisional morphogenesis of protargol stained specimens were analyzed to establish a natural classification for the several hypotrich genera involved. Symbols were created for homologous interphase characters and morphogenetic processes and added to schematized computer drawings of the interphase cortical pattern, showing in one image the interphase and its morphogenesis. This method reveals genealogically linked relationships, correlated complex morphogenetic processes and their evolutionary transformation and gives a standardized account of known morphogenetic processes. Three monophyletic groups with their supposed ancestors are recognized, viz. Orthoamphisiellidae n. fam. and the two sister groups Oxytrichidae Ehrenberg, 1838 and Parakahliellidae n. fam. Species presently assigned to the Oxytrichidae are highly evolved species of two sister groups which separates the species presently assigned to the Oxytrichidae and Stylonychia into two phylongenetic lineages. The three monophyletic groups are separated by complex early morphogenetic anlagen developments in the two rightmost ventral cirral rows. These cirral rows are generated in the Oxytrichidae and the Parakahliellidae by "neokinetal 1" anlagen developments. In contrast, the Orthoamphisiellidae develop these two cirral rows by usual "within" anlagen. The two sister groups are separated from each other by generating "neokinetal 3" anlagen and long primary primordia in the Oxytrichidae and "neokinetal 1" anlagen and separate primary primordia in the Parakahliellidae. Dorsomarginal kineties develop in the Parakahliellidae and highly evolved Oxytrichidae. Dorsal kineties develop in all groups from not more than three within anlagen. The left fronto-ventral field evolved independently from evolutionary changes in the two rightmost ventral cirral rows. The Amphisiellidae and the Kahliellidiae are junior synonyms of the Oxytrichidae. Suggested for Stylonychia pustulata and S. vorax are locations in Clara n. g. as Clara pustulata and C. vorax (new combinations). Results are in accordance with those obtained from molecular techniques.