Monocyrtoceras

Monocyrtoceras is a genus of armenoceratids (Cephalopoda) from the Middle Silurian of North America (Wisconsin), with a gently curved shell and a siphuncle like that of Elrodoceras.

According to Teichert, 1964, in the Treatise part K, Monocyrtoceras along with Elrodoceras and Armenoceras forms one of the two branches of the Armenoceratidae.