Cyptendoceras is an extinct nautiloid cephalopod included in the family Ellesmeroceratidae that lived in what would be North and South America during the latter part of the Early Ordovician (late Arenig) from about 475 – 472 mya, existing for approximately .Cyptendoceras at Fossilworks.org
Taxonomy Cyptendoceras was named by Ulrich and Foerste (1936). Teichert (1964,Curt Teichert, 1964. Endoceratoidea, in the Treatise on Invertebrate Paleontology, Part K, Mollusca 3; Geol Soc of Amer, and Univ. of Kans. press. in the Treatise), included it in the endocerid family Proterocameroceratidae. Flower (1964)Flower 1964. The Nautiloid Order Ellesmeroceratida (Cephalopods), Memoir 12; New Mexico State Bureau of Mines and Mineral Resources, Socorro. NM assigned it to the Baltoceratidae, at that time included in the Ellesmeroceratida. Kroger et al. (2007)Kroger et al., 2007. Early orthoceratoid cephalopods from the Argentine Precordillera; Journal of Paleontology Nov 2007; v. 81; no. 6; pp 1266-1283 reassigned it to the Ellesmeroceratidae on the basis of the ellesmeroceratid type siphuncle, removing it from the Baltoceratidae which had been reassigned to the Orthocerida.
Distribution Fossils of Cyptendoceras have been found in Argentina, Bolivia and the United States (Minnesota, Nevada, New Mexico, Texas, Vermont).
References
Further reading Fossils (Smithsonian Handbooks) by David Ward