Wutinoceras

It exhibits orthoconic actinocerids with ventral siphuncles composed of broadly expanded segments.

Septal necks, components of the siphuncle that project from the back side of the septa, are cyrtochoanitic (outwardly curved) and may be recumbent.

The three varieties of Wutinoceras are based on the form of the siphuncle, and each contains a number of species.

Wutinoceras may have its origin in the primitive actinocerid Georgina from the upper Lower Ordovician of Northern Australia and east Asia[4] although its exact ancestor remains elusive.

[1][2] Wutinoceras is also the ancestor of the Armenoceratidae which gave rise in the later Middle Ordovician to Actinoceras and Gonioceras.