Morphology of the microfossil Polysphaeroides filiformis and of modern cyanobacteria and a modern red alga
Microphotographs of Polysphaeroides filiformis (A and B), Stigonema robustum CBFS-A027 (C), Stigonema informe CBFS-A033 (D) and Bangiopsis franklynottii CCMP3416 (E and F).
(A) black arrows show ICIs within fossil cells.
(B) True T-type branching of the filament.
(C and F) True T-type branching is visible for all the species.
(E) Unbranched filament of B. franklinottii also showing the two types of cells: spherical or flat cells. (Scale bars: A, D, and E = 50 μm; B, C, and F = 100 μm).