Ultrastructure and evolution of a sperm: phylogenetic implications of altered motile machinery in Ophryotrocha puerilis spermatozoon.
Modifications to the mitochondria and flagellum of the Ophryotrocha spermatozoon render it immotile. The sperm may represent an evolutionary unstable intermediate between flagellate and aflagellate sperm types.
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D005075:Biological Evolution; D002502:Centrioles / Q000648:ultrastructure; D008297:Male; D008928:Mitochondria / Q000648:ultrastructure; D011077:Polychaeta / Q000502:physiology*; D013082:Sperm Tail / Q000648:ultrastructure; D013094:Spermatozoa / Q000648:ultrastructure*