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 holochoanitic, 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. References Further reading Teichert, C. 1964. Endoceratoidea. Treatise on Invertebrate Paleontology, Part K. Endoceratoidea, Actinoceratoidea, Nautiloidea. Geological Soc. of America and Univ. Kansas Press External links Allocotoceras -Paleodb † Ordovician cephalopods of Oceania Ordovician Australia Darriwilian Fossils of Australia Paleontology in Tasmania Fossil taxa described in 1953