Ciliopharyngiella intermedia (Plathelminthes, Neoophora) - enigmatic as ever? Ultrastructural features and phylogenetic implications

Ultrastructural features of the epidermis, gonads and photoreceptors are presented. The following features of Ciliopharyngiella intermedia are considered to represent autapomorphies of this species or of the taxon Ciliophatyngiella: the special design of egg shell-forming granules in vitellocytes, the pattern of marginal granules in germocytes,. an intercentriolar body with strong striated supporting beams, cilia with a pair of rootlets in young spermatids, as well as intracerebral photoreceptors with both ciliary and rhabdomeric light-sensing organelles arising from the same cell. Based on present information it is hypothesized, that Ciliophatyngiella represents the sister taxon of the Eulecithophora (= Prolecithophora + Rhabdocoela).