''Clitendoceras'' is a genus of cephalopods in the order

Endocerida Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silu ...

from the

Lower Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. Th ...

(m-u

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

) with an elongate shell with a slight downward, endogastric, curvature and a siphuncle that lies along the ventral margin. Common for endocerids, the chambers are short and the septa close spaced with sutures sloping forward across the back of the shell. Septal necks are short in the young, lengthening in the adult. Endocones are simple, but with the ventral side of the last formed projecting forward. The endosiphotube running down the middle is arched on top and somewhat flat on the lower side. ''Clitendoceras'' appears early in the Domingian stage, Lower Ordovician, probably derived from '' Proendoceras'', and is the likely ancestor of the mostly compressed and breviconic pilocerids as well as of more similar forms such as ''

Mcqueenoceras ''Mcqueenoceras'' is an extinct genus of early endocerid, a nautiloid from the Floian epoch of the late early Ordovician period. It was similar in overall form to '' Clitendoceras'', from which it may have been derived. ''Mcqueenoceras'', like '' ...

''.

References

* Flower, R. H. 1964; Memoir 12,The Nautiloid Order Ellesmeroceratida (Cephalopoda),pp145,150,158.NMBM&MR, Socorro N.M. * Flower, R.H. 1976; Ordovician Cephalopod Faunas and Their Role in Correlation, pp 531–535; proceedings pub. Paleontological Association, Gr Br. * Teichert, C, 1964, ''Clitendoceras'', p 166 in Proterocameroceratidae, pp 166– 170 in the ''Treatise on Invertebrate Paleontology'' Vol K. GSA and Univ Kansas Press. {{Taxonbar, from=Q5134435 Prehistoric nautiloid genera Ordovician cephalopods Ordovician cephalopods of North America