An update of ‘basic light and scanning electron microscopic methods for taxonomic studies of ciliated protozoa’

This is an update of the review by Foissner (1991). Since then, I have improved some methods considerably. The following methods are described in detail: live observation, supravital staining with methyl green-pyronin, dry silver nitrate impregnation, wet silver nitrate impregnation, silver carbonate impregnation, protargol impregnation (three procedures), scanning electron microscopy, and deciliation. Familiarity with these methods (or modifications) is a prerequisite for successful taxonomic work. No staining method is equally appropriate to all kinds of ciliates. A table is provided which indicates those procedures which work best for certain groups of ciliates. A second table relates to the structures revealed by the procedures. Good descriptions usually demand at least live observation, silver nitrate and protargol or silver carbonate impregnation. Some instructions are provided for distinguishing mono- and dikinetids as well as ciliated and non-ciliated basal bodies in silvered ciliates. Furthermore, I added a section on 'Deposition and Labeling of Preparations'. All methods work not only with ciliates but also with many other heterotrophic and autotrophic flagellated and amoeboid protists. The brilliancy of silver preparations has tempted some taxonomists to neglect live observation. However, many important species characteristics cannot be seen or are changed in silvered specimens. I thus consider all species descriptions based exclusively on silver slides as incomplete and of doubtful value for both α-taxonomists and ecologists.