Clitendoceras
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| Clitendoceras Fossil range: LOrdovician(mid-late Canad) |
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Clitendoceras is a member of the Endocerida from the Lower Ordovician (m-u Canad ) with an elongate shell with a slight downward, endogastric, curvature and a siphuncle that lay 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 of the Lower Ordovician ( Canadian ), 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.
[edit] 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.
