Ultrastructure of spermiogenesis and the spermatozoon in Castrada cristatispina Papi, 1951 (Platyhelminthes, Rhabdocoela, Typhloplanida)

摘要: Culioli, J.-L., Foata, J., Mori, C., Orsini, A. and Marchand, B. 2004. Ultrastruc- ture of spermiogenesis the spermatozoon in Castrada cristatispina Papi, 1951 (Platyhelminthes, Rhabdocoela, Typhloplanida). — Acta Zoologica (Stockholm) 85 : 245-256 Spermiogenesis begins with formation a zone differentiation containing two centrioles associated striated rootlets an intercentriolar body between them. The give rise to parallel, free flagella Trepaxonemata 9 + '1' pattern, growing out opposite directions. Spermatids undergo latero-ventral rotation subsequent disto-proximal centrioles, distal cytoplasmic projection appears. former involves compression row microtubules allows recognition ventral side dorsal side. At end differentiation, cortical lie parallel sperm axis. modifications migration nucleus toward are described. mature C. is filiform, tapered at both ends shares several features other Rhabdocoela gametes. Nevertheless, posterior extremity capped by electron-dense material. A gradient mitochondria dense bodies exists along This study has enable us phylogenetic approach through comparison ultrastructural taxa. We propose as synapomorphy Rhabdocoela.