Spermiogenesis in a Scutariellid (Platyhelminthes)

摘要: Spermiogenesis and spermatozoa were studied by transmission scanning electron microscopy in Troglocaridicolasp., a scutariellid epizoic on cavernicolous freshwater shrimp. involves elongation of the spermatid which nucleus elongates, but remains close to common cytoplasmic mass. Flagella first grow opposite direction at right angle shaft, centrioles show associate structures. Later, two rotate flagella emerge parallel, still perpendicular shaft. An apical process elongates extremity The spermatozoon shows active flagellar beating undulations sperm body. comprises an anterior ‘corkscrew’ region, insertion region posterior nuclear region. corkscrew contains dense structure, not membrane-bound, originating from spermatid. 9+‘1’ pattern, usual Platyhelminthes. regions cortical row about 50 twisted longitudinal microtubules surrounding dense, 25-nm granules. These granules are original structures seem be known only few Platyhelminthes species non-flagellar movement occurs. Thus, it is hypothesised that play role cellular motility. Sperm ultrastructure Troglocaridicolashows major differences temnocephalids. It therefore concluded phylogenetic position scutariellids within Temnocephalidea should reinvestigated.