Cephalopoda
Order

Orthocerida Kuhn, 1940

https://files.geocollections.info/large/13/32/13329cfe-6c5b-4554-af54-449d2a9fb5a4.jpghttps://files.geocollections.info/large/a0/2b/a02bfb68-e802-440b-85c6-2ec6402469d5.jpghttps://files.geocollections.info/large/b2/a8/b2a87799-920f-47f2-ba94-906beac37c20.jpghttps://files.geocollections.info/large/87/16/87169ad8-ad0f-4f03-bc2e-8f166461c3fb.jpghttps://files.geocollections.info/large/1a/de/1ade8440-d534-412e-83d6-3400226de5fa.jpghttps://files.geocollections.info/large/eb/a4/eba4fe27-7977-48b0-a5bb-3b93f96946c8.jpghttps://files.geocollections.info/large/8b/65/8b65d03e-bc36-4f2b-b6ae-6d1ba2608b86.jpghttps://files.geocollections.info/large/e0/fa/e0fac121-0f80-4882-b117-eeffc75ea546.jpghttps://files.geocollections.info/large/ee/5e/ee5e39b9-3bce-48df-b308-bd4e5db22433.jpghttps://files.geocollections.info/large/af/a7/afa712f1-282b-446e-a4bc-e8b34abe9944.jpg
Taxon description

Kröger & Isakar, 2006

Emended diagnosis. Straight or curved with smooth orelaborately ornamented shells, with central or subcentral nar-row siphuncle siphuncle that may be slightly expanded be-tween the chambers. Siphuncular necks achoanitic, subortho-choanitic or orthochoanitic. Apex spherical, bowl-shaped orblunt, invariably without cicatrix

Selection of related publications
Kröger, B., Aubrechtová, M. 2019. The cephalopods of the Kullsberg Limestone Formation, Upper Ordovician, central Sweden and the effects of reef diversification on cephalopod diversity. Journal of Systematic Palaeontology 17, 12, 961-995. DOI:10.1080/14772019.2018.1491899
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.
King, A. H. 1999. A Review of Volkhovian and Kundan (Arenig-Llanvirn) Nautiloids from Sweden.Advancing Research on Living and Fossil Cephalopods , pp. 137-159. Springer. DOI:10.1007/978-1-4615-4837-9_11
Kiselev, G. N. 1991. Revizia pozdneordovikskikh i siluriskikh tsefalopod Pribaltiki iz kollektsii E. I. Eichwalda. Bulletin of the Moscow Society of Naturalists. Geological series 66, 4, 85-101.
Rõõmusoks, A. 1970. Stratigraphy of the Viruan Series (Middle Ordovician) in Northern Estonia, I. pp. 1-346. Valgus.
Saladžius, V. J. 1966. Mollusk fauna of the Silurian deposits of the south of the East Baltic territory.Palaeontology and stratigraphy of the Baltic and the Byelorussia. Number I (VI) , pp. 31-73. Mintis.
Balashov, E. A. 1959. Nekotorye novye vidy nautiloidej ordovika, silura i devona SSSR.Materialy k "Osnovam paleontologii", Bypusk 3 , pp. 37-46. Paleontologicheskii Institut Akademii Nauk SSSR.
Sweet, W. C. 1958. The Middle Ordovician of the Oslo Region, Norway: 10. Nautiloid Cephalopods. Norsk Geologisk Tidsskrift 38, 1, 1-176.
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.
Balashov, Z. G. 1955. Semejstvo Cochlioceratidae nom. nov.. Voprosy paleontologii II, 55-60. Izdatel'stvo Leningradskogo Universiteta.
Stumbur, H. 1955. Eesti NSV ülem-ordoviitsiumi nautiloiididest [Diplomitöö]. 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.
Strand, T. 1934. The Upper Ordovician Cephalopods of the Oslo Area. Norsk Geologisk Tidsskrift 14, 1-117.
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. 1860. Lethaea Rossica ou Paléontologie de la Russie. Premier volume. Ancienne Période en deux sections. pp. XIX+1–1657. E. Schweizerbart. DOI:10.5962/bhl.title.52391
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.