Dawsonoceras Hyatt, 1884

Taxon description

Kröger & Isakar, 2006

Emended diagnosis. Slender, circular or slightly compressed orthocones with symmetrically curved septa and straight transverse sutures. Sutures parallel to the annulationsin each groove of the annulations. Annulations regularly spaced, with fine transverse ornament, or growth lines. Growth lines in some species festooned. In some specie slongitudinal ridges that may form nodes at the ridges of the annulations. Siphuncle subcentral in early growth stages, central in late growth stages, narrow, but expanded within the chambers. Septal necks short suborthochoanitic to achoanitic, in advanced forms short reticulate. Incipient annulosiphuncular deposits, and mural cameral deposits are known.

Selection of related publications
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
Kiselev, G. N. 1991. Revizia pozdneordovikskikh i siluriskikh tsefalopod Pribaltiki iz kollektsii E. I. Eichwalda. Bulletin of Moscow Society of Naturalists. Geology 66, 4, 85-101.
Stumbur, H. 1955. Eesti NSV ülem-ordoviitsiumi nautiloiididest [Diplomitöö].