''Campendoceras'' is a genus of proterocameroceratids 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. The ...

of NW

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

and possibly

Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, a ...

that can be recognized by its slender, weakly endogastric, longiconic and annulate shell and large marginal

siphuncle The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...

that contains endocones. The curvature in ''Campendoceras'' is less distinct than that in ''

Clitendoceras ''Clitendoceras'' is a genus of cephalopods in the order Endocerida from the Lower Ordovician (m-u Canadian) with an elongate shell with a slight downward, endogastric, curvature and a siphuncle that lies along the ventral margin. Common for end ...

'' or ''

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 '' ...

'' and the siphuncle is larger.

References

* Teichert, C, 1964. Proterocameroceratidae, pp 166– 170 in the

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

Part K. Geol Soc of America and Univ of Kansas Press. {{Taxonbar, from=Q5028259 Prehistoric nautiloid genera Ordovician cephalopods Prehistoric invertebrates of Oceania Molluscs of Oceania