Cyamocephalus is a genus of synziphosurine,[1] a paraphyletic group of fossil chelicerate arthropods.

[2][3] Cyamocephalus was regarded as part of the clade Planaterga.

[2][4][5][6][3][7] Fossils of the single and type species, C. loganensis, have been discovered in deposits of the Silurian-aged Patrick Burn Formation in Lesmahagow, Scotland (in the United Kingdom).

Cyamocephalus is one of the two members of the family Pseudoniscidae, the other being Pseudoniscus.

[1][7][2] Cyamocephalus differ from Pseudoniscus by the fused tergites of 6th and 7th opisthosomal segments.