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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 902

Michel Tuffrau, Helene Tuffrau, and Jean Genermont; [La reorganisation infraciliaire au cours de la conjugasion et l'origine du promordium buccal dans le genre Euplotes]. J.Protozool. 23(4):517-523, 1976

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During conjugation of Euplotes, the ventral ciliature, including the entire oral apparatus, all the fronto-ventral and transverse cirri, and some of the caudal cirri, is nearly completely lost. As followed in silver-stained preparations, the redifferentiation of the ciliature proceeds in 2 steps. The first step entails differentiation of a new complement of cirri, expect for cirrus 1/I (according to the nomenclature of Wallengren), and neoformation of the anterior part of the adoral zone of membranelles (AZM) form a primordium located in an area that would be expected to give rise to the missing 1/I cirrus. The 2nd step involves replacement of all the cirri, including 1/I, and completion of the oral apparatus by redifferentiation of the posterior half of the AZM and of the paroral ciliature. The spatial morphogenetic relationships between cirrus 1/I and the paroral ciliature suggest that the area of this "paroral cirrus" is homologous with the stomatogenic areas of other Hypotrichida, such as Kahliella and Stylonychia.