Larissa Araguaia Monteiro de Castro, Inácio Domingos da Silva-Neto, Thiago da Silva Paiva


Physiological reorganization is described for the first timed for the hypotrichous ciliate genus Apoamphisiella FOISSNER, 1997, based on a population of A. vernalis (STOKES, 1887) BERGER, 2006 collected from an eutrophic pond in the state of Minas Gerais, Brazil. Stomatogenesis is epiapokinetal, and the cirral pattern reorganizes from six typical fronto-ventral-transverse primordia, plus at least one short primordium located between IV and V. Primordia I and II originate from disaggregating undulating membranes and buccal cirrus, respectively; primordium III originates from left frontoventral cirrus plus a streak of basal bodies extending from the distal end of oral primordium; primordium IV and the short extra primordia are formed from basal bodies perhaps associated to the proximal end of III plus the disaggregation of anteriormost cirri of the left ventral row. Sometimes, the right frontoventral cirrus is incorporated by primordium IV. Primordia V and VI arise within the right ventral row as a single streak, splitting to form the two primordia. Marginal primordia develop initially within the pre-existent marginal rows, continuing to reorganize outside, pushing the old marginal cirri leftwards. Two dorsomarginal kineties develop associated to the right marginal row primordium. Dorsal ciliature also reorganizes from within the pre-existent dorsal kineties. The two macronuclear nodules approach each in middle reorganizers, briefly touching each other. At least one micronucleus undergo division. The process of physiological reorganization in A. vernalis resembles that of the North American Paraurostyla weissei complex representative, and along with features of the interphase morphology, indicate that Apoamphisiella belongs or is related to the Cyrtohymena-Paraurostyla group, within the Dorsomarginalia BERGER, 2006.

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