Summary The cortex of Paramecium behaves as a mosaic of territories expressing different morphogenetic behavior in the course of cell division, being made up of both hyperduplicated and invariant regions, i.e. regions transmitted unchanged from one generation to the next. In this paper, we analyze the dynamics of an extensive network of acetylated microtubules associated with a specific region of the interphase cell, the A-paratene area. The A-paratene-associated microtubules exhibit stability properties similar in behavior to microtubules observed in epithelial cells: they are cold labile but nocodazole resistant. When the cell divides, at least a large part of the A-paratene area behaves as an invariant region. The A-paratene-associated microtubules depolymerize in two steps, accompanying and following the basal body wave, respectively; then, they reassemble after cell separation. Although the invariant region and the A-paratene area do not strictly coincide and microtubule dynamics involve other mechanisms in addition to acetylation, these results strongly suggest that the deployment of this network might correlate with the invariance property of this territory and could be related to its morphogenetic history.