''Ellinoceras'' is a genus of small, straight,

annulate In organic chemistry annulation (from the Latin ''anellus'' for "little ring"; occasionally annelation) is a chemical reaction in which a new ring is constructed on a molecule. : Examples are the Robinson annulation, Danheiser annulation and cert ...

actinoceratid from the Middle

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. ...

of northeastern Siberia with strongly sinuous sutures and subcentral

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 ...

. Sutures have 14 narrow lobes and saddles, the ventral lobe deep and broad with a small median saddle. The

segments are short and broad with short necks and a wide endosiphuncular tube. ''Ellinoceras'' somewhat only superficially resembles other members of the Actinoceratidae and is distinct mainly by its sinuous sutures.

References

*Curt Teichert 1964 Acinoceratoidea.

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 Mollusca 3. Geological Society of America and University of Kansas Press. * Prehistoric nautiloid genera {{paleo-Nautiloidea-stub