exoschizon exoschizon exoschizon is a genus in the phylum apicomplexa. exoschizon scientific classification domain: eukaryota (unranked): sar (unranked): alveolata phylum: apicomplexa class: conoidasida subclass: gregarinasina order: archigregarinorida family: exoschizonidae genus: exoschizon history this genus was created by levine in 1971. taxonomy there is one genus currently recognised in this family - exoschizon. this genus has only one species - exoschizon siphonosomae - which was described by hukui in 1939. description this species was found in the intestine of a sipunculid worm (siphonosoma cumanense) in japan. the meronts measure 90 µm × 15 µm. there are ~13 longitudinal striations per side. the meronts and gamonts are similarly shaped. transmission is presumably by the orofaecal route.