Pospekhova N.A. 2017. Location of the primary lacuna in the postembryonic development of selected Cyclophyllidea (Cestoda): a review // Invertebrate Zoology. Vol.14. No.2: 167–173 [in English].
Institute of Biological Problems of the North, Far Eastern Branch of Russian Academy of Sciences, Magadan 685000, Russia. E-mail: email@example.com
ABSTRACT: The postembryonic development of most cyclophyllids within the intermediate host includes one invagination. This positions the remnants of the primary lacuna between the walls of the dense cyst. Some diplocysts, floricerci and ascocerci undergo two invaginations. In fully formed larvocysts belonging to these types, the remnants of the primary cavity are located between the walls of the additional outer envelope (exocyst). The presence or absence of a primary lacuna is the key characteristic used for metacestode classification. Nonetheless, the position of the primary lacuna during post-embryogenesis may also be important for understanding the evolution of the cestode lifecycle and phylogenetic relations among cyclophyllids.
KEY WORDS: metacestode, cysticercoid, diplocyst, ascocercus, primary lacuna.