Order
Pseudorthocerida Flower et Caster, 1935
Selection of related publications
Kröger, B. 2025. The Lyckholm acme of cephalopods – Review of the late Katian (Vormsi–Pirgu regional stages) Ordovician cephalopods of Estonia.  European Journal of Taxonomy   978,      1-169. DOI:10.5852/ejt.2025.978.2801
Manda, Š., Turek, V. 2015. Colour patterns on Silurian orthocerid and pseudorthocerid Conchs from Gotland - palaeoecological implications.  Estonian Journal of Earth Sciences   64,   1,   74-79. DOI:10.3176/earth.2015.13
Stumbur, H. A. 1956. On the nautiloids of Kohila Subseries (Upper Ordovician of East Baltic).  Tartu Riikliku Ülikooli Toimetised   42,      176-185.
Stumbur, H. 1955. Eesti NSV ülem-ordoviitsiumi nautiloiididest [Diplomitöö. Juhendaja: A. Rõõmusoks]. pp. 1-159.
List of species
3. Spyroceras perlaeve (Strand, 1934) | Upper Ordovician
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Classification
| Organism group | Biota | 
| Kingdom | Animalia | 
| Phylum | Mollusca | 
| Class | Cephalopoda | 
| Subclass | Orthoceratia | 
| Order | Astroviida | 
| Bajkalocerida | |
| Dissidoceratida | |
| Endoceratida | |
| Orthocerida | |
| Pseudorthocerida | |
| Family | Pseudorthoceratidae | 
| Spyroceratidae | |
| Genus | Lyecoceras | 
| Order | Rioceratida | 
 See also