title: Uniflagellate spermatozoa in Nemertoderma (Turbellaria) and their phylogenetic significance.
abstract: An ultrastructural study of Nemertoderma (Turbellaria, Nemertodermatida) has revealed that its spermatozoa have only a single falgellum. This is the first uniflagellate spermatozoon known in the Turbellaria; it is indicative of the primitiveness of Nemertoderma and is evidence in support of the view that the Turbellaria as a whole are among the most primitive living Bilateria.
mesh_terms: D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D005075:Biological Evolution; D002467:Cell Nucleus / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D010802:Phylogeny; D013082:Sperm Tail / Q000648:ultrastructure*; D013094:Spermatozoa / Q000648:ultrastructure*; D014419:Turbellaria / Q000145:classification / Q000254:growth & development / Q000648:ultrastructure*