Zemistephanus
Appearance
Zemistephanus Temporal range: Jurassic
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Genus: | Zemistephanus McLearn, 1927
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Zemistephanus is an extinct ammonite genus from the middle Jurassic of western North America and Western Australia, named by McLearn 1927. Zemistephanus is included in the sephanoceratoid family Otoitidae, which are characterized by shells that begin as barrel-shaped cadicones but which become planulate later in life. Body chambers are reduced in size and are excentric. Similar genera are Pseudotoites and Emileia
References
This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (October 2013) |
- Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.