Life cycle and ultrastructure of Lagotia minor dons, 1948 (Ciliophora, Heterotrichia) revealing new characters for folliculinid classification

The morphology, behavior, trophont ultrastructure, and life cycle of the folliculinid species, Lagotia minor, is described. Lagotia minor has a simple lorica, a rounded macronucleus, broad and stiff peristomial wings, and a deep buccal cavity. The behavior of the swarmer and its mode of lorica secretion differ from these events in Eufolliculina and Metafolliculina. The ultrastructural investigations reveal further differences between the genera, e.g., in Lagotia minor the somatic dikinetids are associated with a cross-striated fiber which runs along the postciliary ribbon. The peristome of L. minor is supported from ladder-like nemadesmata which originate from opposite sides of the wings. Based on these results and on light microscopical observations on other folliculinid genera, new characters for folliculinid classification are discussed.