Cyrtoceras is an extinct genus of oncoceridan nautiloids that lived from the middle Ordovician to the middle Devonian, in Africa, Europe, North America and South America.
References
- ^ Teiichi KOBAYASHI (1987). "The Ancestry of the Cephalopoda: From Helcionella to Plectronoceras". Proceedings of the Japan Academy, Series B: Physical and Biological Sciences. 63 (5): 135–138. Bibcode:1987PJAB...63..135K. doi:10.2183/pjab.63.135.
Sources
- Fossils (Smithsonian Handbooks) by David Ward
- Fossils (A Golden Guide from St. Martin's Press) by Frank H. T. Rhodes, Paul R. Shaffer, Herbert S. Zim, and Raymond Perlman
- Aquagenesis: The Origin and Evolution of Life in the Sea by Richard Ellis
External links
- Cyrtoceras in the Paleobiology Database