Stomatogenesis during cell division in the loricate ciliate Eufolliculina uhligi: A scanning electron microscope...

Unlike most other ciliates, folliculinids divide into two physiologically and morphologically different cells: the anterior cell part (proter) becomes a non-feeding motile swarmer, the posterior part (opisthe) remains sessile and develops a new oral apparatus. After settling, the swarmer transforms into a sessile cell (metamorphosis). Division of the loricate ciliate Eufolliculina uhligi has been studied by scanning electron microscopy (SEM). Stomatogenesis in many aspects resembles that during metamorphosis. Eight stages can be distinguished. Stage 0 is characterized by the resorption of the old oral apparatus. New cilia arise from somatic kineties in a single, well-defined area. Two primordia of different sizes appear. The long, hook-shaped primordium of the opisthe gives rise to the AZM around the peristomial wings and to the paroral kinety. While the opisthe develops a functioning oral apparatus, the proter forms neither a buccal cavity nor a cytostome, and its oral ciliature is reduced. Stomatogenesis during cell division and during metamorphosis in E. uhligi is compared to that in motile heterotrichs, especially Stentor.