Species

Dawsonoceras fenestratum (Eichwald, 1860)

Taxon description

Kröger & Isakar, 2006

Diagnosis. Dawsonoceras with an apical angle of < 10° in juvenile stages. Tubular adult living chamber of approximately 25 mm in diameter. Five to six annulations at distance equal to shell diameter. Approximately, 20 longitudinal striae around the shell circumference, approximately fifteen growth lines or transverse striae per cycle of annulations. Septal necks achoanitic. Siphuncle subcentral, expanded within the chambers.

Synonymy list

1858 Orthoceras calamiteum Portlock, 1843 — Schmidt , pp. 197

1859 Cycloceras fenestratum — Eichwald , fig. 48:14

1860 Cycloceras fenestratum m. — Eichwald , pp. 1231-1232

1880 Orthoceras funiforme — Angelin , pp. 2, fig. 7:18-20

1889 Orthoceras funiforme — Rüdiger , pp. 59

1889 Cycloceras fenestratum — Rüdiger , pp. 59

1925 Orthoceras fenestratum Eichwald — Bekker

1962 Cedarvilleoceras porkunense — Balashov & Zhuravleva , fig. 13:9

1984 Cedarvilleoceras porkunense — Dzik , pp. 125, fig. text fig. 49.21

1988 Calorthoceras (Hornyoceras) lineatum — Kiselev , pp. 81, fig. text fig. 3

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. 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

Classification

Organism group	Biota
Kingdom	Animalia
Phylum	Mollusca
Class	Cephalopoda
Subclass	Orthoceratia
Order	Orthocerida
Suborder	Orthoceratina
Family	Dawsonoceratidae
Genus	Dawsonoceras
Species	annulatum
	barrandei
	fenestratum
	funiforme
	gregarium
	obsoletum