Genus

Striatocycloceras Kröger et Isakar, 2006

Taxon description

Kröger & Isakar, 2006

Diagnosis. Slender, circular or slightly compressed orthocones with asymmetrically curved septa and straight transverse or slightly oblique sutures. Sutures parallel, or nearly so, to the annulations. Annulations slightly irregularly spaced, with fine transverse ornament. Siphuncle eccentric, narrow, tubular or slightly expanded within the chambers. Septal necks orthochoanitic. Cameral and endosiphuncular deposits not 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., 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

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

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.

List of species

1. Striatocycloceras foerstei (Teichert, 1930) | Vormsi Stage

2. Striatocycloceras hosholmense Kröger, 2025 | Pirgu Stage

3. Striatocycloceras isbergi Kröger, 2013 | Vormsi Stage

4. Striatocycloceras obliquum (Eichwald, 1857) | Nabala Stage

5. Striatocycloceras romingeri (Foerste, 1932) | Haljala Stage→Rakvere Stage

6. Striatocycloceras undulostriatum (Hall, 1847) | Lasnamägi Stage→Vormsi Stage

Classification

Organism group	Biota
Kingdom	Animalia
Phylum	Mollusca
Class	Cephalopoda
Subclass	Orthoceratia
Order	Orthocerida
Suborder	Orthoceratina
Family	Orthoceratidae
Subfamily	Orthoceratinae
Genus	Ctenoceras
	Orthoceras
	Orthocycloceras
	Striatocycloceras
Species	foerstei
	hosholmense
	isbergi
	obliquum
	romingeri
	undulostriatum