CONICET | Buscador de Institutos y Recursos Humanos

This study aims at describing the morphology and certain morphogenetic stages of a new ciliate species from Argentina within the genus Deviata. Samples were taken from a temporary freshwater pond near the city of Dolores, Buenos Aires Province. Cultures were made by adding table water and a wheat grain to the samples in Petri dishes. Ciliates were studied alive and after silver impregnation with Protargol. Deviata sp. measures 130-180 µm x 45-70 µm in vivo and its cytoplasm appears dark grey because of the presence of refractive globules. The species possesses 8-9 long cirral rows on the right and 9-13 on the left of the buccal cavity, and 3 long dorsal rows of dikinetids. The adoral zone is composed of 39-48 membranelles; paroral extends beyond the distal end of the endoral membrane. There are 4 macronuclear nodules and usually 2 micronuclei. A single contractile vacuole is located equatorially on the left body margin. During the morphogenesis of cell division the anlage 4 for the proter develops from disaggregated cirri from row R4. The anlage 4 for the opisthe develops probably from the oral primordium and from disaggregated cirri from row R5. This new species mainly differs morphologically from its congeners in having a high number of cirral rows, the 3 long dorsal rows of dikinetids, and a high number of adoral membranelles. Concerning the morphogenesis during cell division, the two right-most ventral rows of cirri replicate as in D. abbrevescens Eigner, 1995, but the development of anlagen 4 is different in both species.