''Manitoulinoceras'' is a genus of Late Ordovician oncocerid

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 ...

cephalopods, found in North America (Kentucky, Ohio, Indiana, and Ontario). The shell is cyrtoconic, exogastric, more strongly curved than in ''

Kindleoceras ''Kindleoceras'' is a genus of oncocerids belonging to the Valcouroceratidae, extinct nautiloid cephalopods that lived during the Middle and Late Ordovician. ''Kindleoceras'' is characterized by a gently curved or virtually straight shell, the ...

''. The cross-section is somewhat wider than high, with a somewhat flattened upper side, known as the dorsum. Actinosiphonate deposits in the siphuncle are confined to the early part of the phragmocone. ''Staufferoceras'', a valcuouroceratid from the Middle and Upper Ordovician of Minnesota and Ohio named by Foeste, 1932, is much like ''Manitoulinoceras'' but with a living chamber that is swollen in the middle, narrowing toward the aperture.

References

* Walter C Sweet, 1964 Nautiloidea-Oncocerida. Treatise on Invertebrate Paleontology Part K Mollusca 3. Geological Society of America and University of Kansas Press. Prehistoric nautiloid genera Paleozoic life of Ontario Oncocerida {{paleo-nautiloidea-stub