 | This article may be too technical for most readers to understand. (October 2020) |
| Pseudorthocerida Temporal range:
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|---|---|
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| Reticycloceras, a Carboniferous pseudorthocerid | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Orthoceratoidea |
| Order: | †Pseudorthocerida Barskov 1963, from Flower & Caster, 1935 |
Pseudorthocerida is an order of generally straight longiconic orthoceratoids with a subcentral to marginal cyrtochoanitic siphuncle composed of variably expanded segments which may contain internal deposits that may develop into a continuous parietal lining. (Sweet 1964[2]). Cameral deposits are common and concentrated ventrally. Apices typically have a slight to moderate exogastric curvature
The Pseudorthocerida are included in a broad in-group of generally orthoconic cephalopods known as the Orthoceratoidea (Kroger 2008) along with the Ascocerida, Dissidocerida, Lituitida, and Orthocerida.
The Pseudorthocerida were among the last living orthoconic nautiloids. One family, the Trematoceratidae, survived into the Triassic Period.
- ^ Zakharov, Yuri D. (1996). "Orthocerid & ammonoid shell structure: its bearing on cephalopod classification". Bulletin of the National Science Museum. Series C, Geology & Paleontology. 22 (1, 2): 11–35.
- ^ Sweet, Walter C. (1964). Nautiloidea -- Orthocerida, in Treatise on Invertebrate Paleontology. Part K. Mollusca 3. Geological Society of America, and University of Kansas Press, New York, New York and Lawrence, Kansas.