Allocotoceras

Allocotoceras is an endocerid from the Lower Ordovician (upper Canadian) Karmberg Formation of Australia (Tasmania), included in the Endoceratidae, based on small, straight or gently curved siphuncles.
Septal necks, according to Teichert, 1964, are holochoantic, reaching to the previous septum. Endocones are described as having a dorsal wedge, or process, making the internal opening, or endosiphocone, semicircular in cross section. In this sense "Allocotoceras" seems to resemble the genus "Najaceras".