''Danaoceras'' is a

nautiloid Nautiloids are a group of marine cephalopods ( Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and ''Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded species ...

cephalopod from the

middle Silurian Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek (d ...

of central Europe included in the oncoceroid family

Polyelasmoceratidae Polyelasmoceratidae is a family of oncocerid nautiloids characterized by rapidly expanding endogastrically curved shells, curved such that the ventral side is longitudinally concave. In cross section shells are typically tear-drop in shape to su ...

. Similar specimens from the middle Devonian of North America may belong. ''Danaoceras'' has a laterally compressed shell curved such that the ventral or siphuncular side is longitudinally concave, i.e. is endograstric. The siphuncle, which is ventrally submarginal, contains laminar actinosiphonate deposits. ''Danaoceras'' is the ancestral genus of the Polyelasmoceratidae and is possibly derived from either ''

Oonoceras ''Oonoceras'' is an extinct genus of fossil cephalopods included in the nautiloid order Oncocerida and the family Oncoceratidae from the Middle Ordovician to Middle Silurian of North America and Europe, arbitrarily included in the Slender Oncoc ...

'' or ''

Oocerina ''Oocerina'' is an extinct genus of nautiloid cephalopods that lived during the Late Silurian of Europe, Russia, and North America. ''Oocerina'', included in the oncoerid family Oncoceratidae and arbitrarily within the Slender Oncoceratidae, is ...

'' of the

Oncoceratidae Oncoceratidae is a family of nauatiloid cephalopods in the order Oncocerida established by Hyatt, 1884, that range from the Middle Ordovician to the Upper Silurian. Diagnosis Oncoceratidae are characterized by generally compressed, cyrtocon ...

based on similarities of the siphuncle

References

* Walter C. Sweet, 1964. Nautiloidea - Oncocerida; Treatise on Invertebrate Paleontology, Part K. Geological Society of America. Prehistoric nautiloid genera Oncocerida {{paleo-nautiloidea-stub