ABSTRACT
The 4.671 speciose Cestoda are unique for the presence of repetitive proglottids, each with dual reproductive system. Their indirect cycle is viewed by dividing them into: (1) Aquatic and (2) Terrestrial patterns. The former includes (1a) Oncosphere type, in which the procercoid and plerocercoid larval stages are completed within one IH and (1b) Coracidium type, in which these larval stages are completed in two different IHs. The terrestrial pattern includes three types: (i) hexacanth-cysticercoid, (ii) hexacanth-tetrathyridium and (iii) hexacanth-cysticercus. For the first time, the shares of the oncosphere, coracidium and hexacanth types are estimated as 17.0 %, 29.5 % and 46.5 %, respectively. The inclusion of IH in herbivorous/insectivorous food chain seems to have enriched the taenioids as the most speciose (2,264 species) taxa. Amenability to in vitro culture up to adult stage has provided unique opportunity to study the mating system in the hermaphrodite Schistocephalus solidus.
