A protozoan phylum of the Kingdom Protista of the old five kingdom scheme of classification, and includes organisms that share common characteristics such as being one-celled, non-motile, parasitic, and spore-forming
In a former five kingdom scheme of classification, the protozoans are classified into four groups based on their means of locomotion: the flagellates, the amoeboids, the sporozoans, and the ciliates. The sporozoans comprise the phylum Sporozoa. Sporozoans are organisms that are characterized by being one-celled, non-motile, parasitic, and spore-forming. Most of them have an alternation of sexual and asexual stages in their life cycle. An example of sporozoan is the Plasmodium falciparum, which is the causative agent of malaria.
The taxon Sporozoa was proposed in 1879 by German zoologist, Karl Georg Friedrich Rudolf Leuckart. 1 This old scheme of classification though is no longer encouraged for use. The phylum Apicomplexa is used instead. It is comprised of protozoans that are characterized by having a special organelle called an apical complex. Most of them are single-celled, parasitic, and spore-forming.
1 Leuckart, R. (1879). Die menschlichen Parasiten. 2nd ed., Vol. 1., Winter: Leipzig.