Ultrastructure of oocytes and female copulatory organs of Acoela

Abstract

© 2014, Pleiades Publishing, Inc. The ultrastructure of oocytes in four Acoela species representing different families (Archaphanostoma agile, Otocelis rubropunctata, Symsagittifera japonica, and Amphiscolops sp.) and of female copulatory organs (bursae) in S. japonica and Amphiscolops sp. is described for the first time. The sister relationship between the families Sagittiferidae and Convolutidae is confirmed by the similarity of their reproductive apparatus structure. It is suggested the ultrastructure of oocytes and specific features of oogenesis can be used in the phylogenetics of Acoela.