a-j Early and middle stages of morphogenesis in Heterogastrostyla salina nov. spec. after protargol staining. a, e, g, i Ventral views to show the development of oral primordium, fronto-ventral-transverse anlagen and marginal rows anlagen, arrows in (i) indicate dorsomarginal anlagen (dikinetidal row) that originate from the anterior of right marginal anlage. c Showing the resorption of parental undulating membranes (arrow) in the proter as depicted in (a). d Magnified view of the fronto-ventral-transverse anlagen as shown in (e), arrow indicates the small patch of densely distributed kinetids posterior to the frontoventral anlage I in the proter. b, f, h, j Dorsal views to show the development of dorsal kineties and nuclear apparatus. LMA, anlage for the left marginal row; Ma, macronuclear nodules; OP, oral primordium; RMA, anlage for the right marginal row; 1−3, dorsal kineties anlagen 1−3. Scale bars = 40 μm a−j.