Family
Orthoceratidae McCoy, 1844
Taxon description
Kröger & Isakar, 2006
Emended diagnosis. Orthocones with slender, central orsubcentral, tubular or moderately expanded siphuncle. Septalnecks suborthochoanitic or orthochoanitic, respectively. Shellsmooth or annulated, with more or less well developed longi-tudinal and transverse ribs, ridges or combination of these.Ornamentation usually more well-developed in shell parts oflater growth stages. Bowl-shaped apical shell small, straight,without cicatrix, without initial constriction, smooth or orna-mented with transversal and longitudinal elements, but with-out annulations. Endosiphuncular and cameral deposits occuronly in most apical chambers of quasi-mature specimens
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, 1-168. DOI:10.5852/ejt.2025.978.2801
Pohle, A., Klug, C., Toom, U., Kröger, B. 2019. Conch structures, soft-tissue imprints and taphonomy of the Middle Ordovician cephalopod Tragoceras falcatum from Estonia. Fossil Imprint 75, 1, 70-78. DOI:10.2478/if-2019-0006
Kröger, B., Aubrechtová, M. 2018. Cephalopods from reef limestone of the Vasalemma Formation, northern Estonia (latest Sandbian, Upper Ordovician) and the establishment of a local warm-water fauna. Journal of Systematic Palaeontology 16, 10, 799-839. DOI:10.1080/14772019.2017.1347212
Kröger, B. 2013. The cephalopods of the Boda Limestone, Late Ordovician, of Dalarna, Sweden. European Journal of Taxonomy 41, 41, 1-110. DOI:10.5852/ejt.2013.41
Kröger, B., Ebbestad, J. O. R., Högström, A. E. S., Frisk, Ǻ. M. 2011. Mass concentration of Hirnantian cephalopods from the Siljan District, Sweden; taxonomy, palaeoecology and palaeobiogeographic relationships. Fossil Record 14, 1, 35-53. DOI:10.1002/mmng.201000014
Kröger, B. 2007. Concentrations of juvenile and small adult cephalopods in the Hirnantian cherts (Late Ordovician) of Porkuni, Estonia. Acta Palaeontologica Polonica 52, 3, 591–608.
Kröger, B., Isakar, M. 2006. Revision of annulated orthoceridan cephalopods of the Baltoscandic Ordovician. Fossil Record 9, 1, 137-163. DOI:10.1002/mmng.200600005
Kröger, B. 2004. Revision of Middle Ordovician orthoceratacean nautiloids from Baltoscandia. Acta Palaeontologica Polonica 49, 1, 57-74.
Mutvei, H. 2002. Connecting ring structure and its significance for classification of the orthoceratid cephalopods. Acta Palaeontologica Polonica 47, 1, 157-168.
Rõõmusoks, A. 1970. Stratigraphy of the Viruan Series (Middle Ordovician) in Northern Estonia, I. pp. 1-346. Valgus.
Balashov, Z. G. 1956. O sistematicheskom polozhenii i stratigraficheskom znachenii roda Orthoceras. Ežegodnik Vsesoûznogo Paleontologičeskogo Obŝestva XV, 223-247.
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.
Alichova, T. N., Balashova, E. A., Balashov, Z. G. 1954. Polevoj atlas harakternyh kompleksov fauny otloženij ordovika i gotlandiâ ûžnoj časti Litovskoj SSR. pp. 1-80. Nedra.
Teichert, C. 1930. Die Cephalopoden-Fauna der Lyckholm-Stufe des Ostbaltikums. Paläontologische Zeitschrift 12, 3/4, 264-312. DOI:10.1007/BF03044452
Öpik, A. 1927. Die Inseln Odensholm und Rogö. Ein Beitrag zur Geologia von NW-Estland. Tartu Ülikooli Geoloogia Instituudi Toimetused 9, 1-69.
Foord, A. H. 1887. On “Orthoceras (Endoceras) duplex” Wahlenberg et auct., with descriptions of three new species of Endoceras from the Ordovician of Sweden and Russia contained in the British Museum (Natural History). Annals and Magazine of Natural History 5, 20, 393–403.
Eichwald, E. 1857. Beitrag zur geographischen Verbreitung der fossilen Thiere Russlands. Alte Periode. (Fortsetzung. S. Bulletin 1856. N 4. pag. 555.). Klasse der Cephalopoden. Bulletin of the Moscow Society of Naturalists. Geological series 30, I, 192-219.
Schlotheim, E. F. von 1820. Die Petrefactenkunde auf ihrem jetzingen Standpuncte durch die Beschreibung seiner Sammlung versteinerter und fossiler Überreste des Thier-und Pfanzenreichs der Vorwelt erläuteri. pp. Ixii+1-436. Becker'sche Buchhandlung.
List of species
1. Balticoceras discors (Eichwald, 1857) | Rakvere Stage
3. Ctenoceras sweeti Kröger et Isakar, 2006 | Lasnamägi Stage
4. Orthoceras arcuolyratum Schmidt, 1858 | Vormsi Stage
7. Orthoceras luhai Stumbur, 1956 | Vormsi Stage
11. Orthocycloceras ibex (Sowerby, 1839) | Silurian
12. Plagiostomoceras fragile Kröger, 2004 | Lasnamägi Stage
15. Pleurorthoceras organi Kröger et Aubrechtová, 2018 | Keila Stage
16. Pleurorthoceras osmundsbergense Kröger, 2013 | Katian
17. Striatocycloceras foerstei (Teichert, 1930) | Vormsi Stage
18. Striatocycloceras hosholmense Kröger, 2025 | Pirgu Stage
19. Striatocycloceras isbergi Kröger, 2013 | Vormsi Stage
20. Striatocycloceras obliquum (Eichwald, 1857) | Nabala Stage
Loading...
Classification
| Organism group | Biota |
| Kingdom | Animalia |
| Phylum | Mollusca |
| Class | Cephalopoda |
| Subclass | Orthoceratia |
| Order | Orthocerida |
| Suborder | Orthoceratina |
| Family | Arionoceratida |
| Arionoceratidae | |
| Dawsonoceratidae | |
| Eriditidae | |
| Geisonoceratidae | |
| Lamellorthoceratidae | |
| Orthoceratidae | |
| Subfamily | Michelinoceratinae |
| Orthoceratinae | |
| Genus | Pleurorthoceras |
| Family | Proteoceratidae |
| Tripteroceratidae |
See also