- A phylum of the subkingdom Protozoa, which includes the class Sporozoea and the subclasses Coccidia and Piroplasmia, and is characterized by the presence of an apical complex. [L. apex, pl. apicis, tip, summit, + complexus, woven together]
* * *Ap·i·com·plexa (ap″ĭ-kəm-plekґsə) [apico- + complex] a phylum of uninucleate, parasitic tissue-dwelling protozoa characterized by an apical complex, with one or more microspores usually present at some stage of development. Flagella and cilia are absent in the adult stage, and many mature apicomplexans glide by means of ultrastructural ridges and fibers on the body surface. They typically reproduce either asexually by means of multiple fission (forming merozoites or schizozoites) or by endodyogeny; or sexually by syngamy. The phylum comprises two classes: Perkinsea and Sporozoea. Called also Sporozoa.
Medical dictionary. 2011.