We are not sure if type IV pili are visible in our EM figures. They are very thin (less than 1 nm) and normally visualized by negative staining. In the published EM figures of Phormidium (conventional and cryo EM), type IV pili have not been noted. The filaments that we see in our EM figures could be components of sheath materials.
In particular, the appearance of bulges in the extracellular sheath adjacent to the site of the junctional pores appears to be consistent with this mode of motility.