Morphogenesis in Amphisiella australis Blatterer and Foissner, 1988 (Ciliophora, Hypotrichida)

Abstract

The cortical morphogenesis of Amphisiella australis Blatterer and Foissner, 1988 was investigated using protargol impregnation. In 43% of the examined cells the morphogenesis starts with a dedifferentiation of the two transverse cirri forming the oral primordium. In the other specimens the oral primordium either originates close to the left intact transverse cirrus (40%) or by dedifferentiation of the left transverse cirrus (16%). In the opisthe 3 anlagen each arise from the oral primordium and from the cirri of the ventral row. 2 anlagen of the proter evolve from the fronto-ventral cirri, 1 from the buccal cirrus, 1 from the undulating membranes, 1 from the cirri of the ventral row, and 1 from the oral primordium of the opisthe. The 6 anlagen are joined in the middle morphogenetic stages; later they separate. Marginal rows and dorsal kineties develop within the parental structures and show no special features. The parental adoral zone of membranelies is retained in the proter, the undulating membranes are partially dedifferentiated. The comparison with the morphogenesis of urostylids and oxytrichids suggests that Amphisiella australis is related to the oxytrichids sensu lato.