The silicoflagellates (order Dictyochales) are a small group of unicellular photosynthetic protists, or algae, belonging to the supergroup of eukaryotes known as Stramenopiles.

The silicoflagellates are unicellular protists, composed of cells with one emergent flagellum and a siliceous skeleton constructed from a network of hollow rods outside of the cytoplasm.

[1] Through morphological and molecular similarities, this group was eventually transferred to the Dictyochophyceae, which contains three additional orders, Pedinellales, Florenciellales and Rhizochromulinales.

[5] After decades of phylogenetic analyses, silicoflagellates and the rest of Dictyochophyceae are accepted as a class of the phylum Ochrophyta, within the eukaryotic supergroup Stramenopiles.

[3] Silicoflagellate skeletons from the Cretaceous are markedly different from Cenozoic ones: before the Santonian (around 85 million years ago) they presented branched, non-ringed shapes.

[13] During the Cenozoic, silicoflagellates show an evolutionary trend towards more complicated apical and basal structures, resulting in a design that resembles a hemisphere.