Morphological description
''Lambeoceras'' is of medium to moderately large size with a long, straight, depressed shell, broad in cross section with the dorsum and venter both about equally convex, meeting acutely along the sides. Chambers are short, and septa are closely spaced, forming broad lobes on the upper and lower sides, which meet in sharp saddles along the sides. The siphuncle is submarginal, near the ventral side and relatively narrow. Septal necks are extremely long, brims short and recumbent. Segments are broadly expanded, connecting rings thin. Radial canals within the siphuncle from broad arcs that may bifurcate close to the parispatium.Derivation and phylogeny
''Lambeoceras'' is derived from the same stock in '' Actinoceras'' that produced ''Kochoceras'' according to Flower (1968), although consideration had been given to '' Armenoceras'' in Flower (1957). Teichert (1964) on the other hand, in the Treatise, thought that ''Lambeoceras'' was derived from '' Gonioceras'' and included it in the Gonioceratidae. ''Kochoceras'' differs from ''Lambeoceras'' in having a flattened venter and a siphuncle that rests on the ventral side and is closely allied with ''Actinoceras'' (Flower 1957)Distribution
''Lambeoceras'' is found with ''Actinoceras'', ''Armenoceras'', and '' Nybyoceras'' in the Second Value Formation inPaleoecology
While the earlier ''Gonioceras'' no doubt rested on the sea floor in ambush, perhaps half buried or more in sediment, ''Lambeoceras'' may have more actively hunted in the water close to but above. On the other hand, ''Lambeoceras'' ' shape may have had more to do with stabilization in shallow surge ridden waters than with hunting methods.References
* Flower, R.H, 1957, Studies of the Actinoceratida, New Mexico Bureau of Mines and Mineral Resources, Memoir 2. * Flower, R.H. 1968, The First Great Expansion of the Actinoceroids; New Mexico Bureau of Mines and Mineral Resources, Memoir 2, Pt i. * Flower, R.H, 1978, Ordovician Cephalopod Faunas and Their Role in Correlation; in The Ordovician System: proceedings of a Palaeontological Association symposium; Bassett, M.G. (Ed) * Teichert, C, 1964, Actinoceratoidea, in the Treatise on Invertebrate Paleontology, pub Univ of Kansas and the GSA, Vol K, p K208-210 {{Taxonbar, from=Q6481197 Ordovician cephalopods of North America Prehistoric cephalopod genera Paleozoic life of Manitoba Paleozoic life of the Northwest Territories Paleozoic life of Nunavut Paleozoic life of Quebec