© 1979 by The Society for Integrative and Comparative Biology
The Impact of Electron Microscopy on Ciliate Systematics
Department of Zoology, University of Maryland College Park, Maryland 207 42
Electron microscopy has been used in research on species of protozoa for some time, but only since about 1970, date of commencement of the so-called Age of Ultrastructure in ciliate systematics, has a conscientious effort been made to apply some of the data so obtained to problems in the taxonomy and evolution of forms included within the phylum Ciliophora. In general, traits revealed by EM studies have obliged ciliatologists to recognize a greater diversity among their organisms than heretofore appreciated. In turn, this has caused a noticeable expansion in the number of suprafamilial taxa recognized today. The increase in data potentially suitable for comparative taxonomic work has been welcomed; and many of the characters now available are new (i.e., not generally or fully visible with light microscopy). Major categories include extrusomes, somatic organelles (components of the kinetid), and oral-area structures. Haifa dozen examples of the direct effect of EM studies on current high-level ciliate classification systems are presented. Figures are included in illustration of ultrastructural and other characters used by (or potentially available to) the taxonomically-inclined ciliatologist.