Family

Dawsonoceratidae Flower, 1962

Taxon description

Kröger & Isakar, 2006

Emended diagnosis. Annulated orthocones with slender,central to subcentral, tubular or moderately expanded si-phuncle. Septal necks very short and can vary betweenachoanitic, suborthochoanitic, or very short cyrtochoanitic insome developed species. Shell ornamented with a reticulatepattern of growth lines and fine longitudinal raised lines, orwith transverse festoons. Apical shell large, without cicatrix,without initial constriction, apex blunt, annulated or smooth,transverse or longitudinal ornamentation may occur. Incipi-ent annulosiphuncular deposits, and mural cameral depositsare known

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

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 [Ревизия позднеордовикских и силурийских цефалопод прибалтики из коллекции Е. И. Эйхвальда]. Bulletin of the Moscow Society of Naturalists. Geological series 66, 4, 85-101.

Stumbur, H. 1955. Eesti NSV ülem-ordoviitsiumi nautiloiididest [Diplomitöö. Juhendaja: A. Rõõmusoks]. pp. 1-159.

Teichert, C. 1930. Die Cephalopoden-Fauna der Lyckholm-Stufe des Ostbaltikums. Paläontologische Zeitschrift 12, 3/4, 264-312. DOI:10.1007/BF03044452

List of species

1. Dawsonoceras annulatum (Sowerby, 1816) | Wenlock

2. Dawsonoceras barrandei Horny, 1956 | Wenlock

3. Dawsonoceras fenestratum (Eichwald, 1860) | Porkuni Stage

4. Dawsonoceras funiforme (Angelin, 1880)

5. Dawsonoceras gregarium Kröger, Ebbestad, Högström et Frisk, 2011 | Hirnantian

6. Dawsonoceras obsoletum (Barrande, 1874) | Paadla Stage→Ohesaare Stage

7. Palaeodawsonocerina nicolletoides Kröger, 2013 | Katian

8. Palaeodawsonocerina senckenbergi (Teichert, 1930) | Keila Stage→Pirgu Stage

Classification

Organism group	Biota
Kingdom	Animalia
Phylum	Mollusca
Class	Cephalopoda
Subclass	Orthoceratia
Order	Orthocerida
Suborder	Orthoceratina
Family	Arionoceratida
	Arionoceratidae
	Dawsonoceratidae
Genus	Dawsonoceras
	Palaeodawsonocerina
Family	Eriditidae
	Geisonoceratidae
	Lamellorthoceratidae
	Orthoceratidae
	Proteoceratidae
	Tripteroceratidae