A Newly Revised Classification of the Protozoa*

Abstract

The subkingdom Protozoa now includes over 65,000 named species, of which over half are fossil and .apprx. 10,000 are parasitic. Among living species, this includes .apprx. 250 parasitic and 11,300 free-living sarcodines (of which .apprx. 4600 are foraminiferids); .apprx. 1800 parasitic and 5100 free-living flagellates; .apprx. 5600 parasitic Sporozoa (including Apicomplexa, Microspora, Myxospora, and Ascetospora); and .apprx. 2500 parasitic and 4700 free-living ciliates. There are undoubtedly thousands more still unnamed. Seven phyla of Protozoa are accepted in this classification: Sarcomastigophora, LABYRINTHOMORPHA phylum nov., Apicomplexa, Microspora, Ascetospora, Myxospora [containing the new class ACTINOSPOREA, which in turn contains the new order ACTINOMYXIDA under the subclass Actinomyxia] and Ciliophora. Diagnoses are given for these and for all higher taxa through suborders, and representative genera of each are named. The present scheme is a considerable revision of the Society''s 1964 classification, which was prepared at a time when perhaps 48,000 spp. had been named. It has been necessitated by the acquisition of a great deal of new taxonomic information, much of it through electron microscopy. It is hoped that the present classification incorporates most of the major changes that will be made for some time, and that it will be used for many years by both protozoologists and non-protozoologists.