Physiological reorganization is described for the fi rst time for the hypotrich 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 anterior end of oral primordium; primordium IV and the short extra primordia are formed from basal bodies
perhaps associated to the posterior end of III plus the disaggregation of anteriormost cirri of the left ventral row. 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, briefl y
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.
|
