Ultrastructure of aflagellate spermatozoa in rhabdocoel turbellarian provortex karlingi (neorhabdocoela, dalyellioida)

Abstract

© 2015 r. The ultrastructure of spermatozoa and spermatids in a the rhabdocoel turbellarian Provortex karlingi from the White Sea is described for the first time. Among the unusual morphological features of spermatozoa, the absence of flagellae and the presence of perinuclear condensation of electron-dense granules are notified. The examples of reduction of flagellae in male gametes of various groups of flatworms are discussed. New data support the monophyly of the turbellarian genus Provortex, which is characterized by the number of some unique synapomorphies