Species

Palaeodawsonocerina senckenbergi (Teichert, 1930)

Taxon description

Kröger & Isakar, 2006

Diagnosis. Straight, slightly compressed with very low apical angle of approximately 1––2. Adult dorsoventral dia-meter approximately 25 mm, with five to six annulations at adistance that equates to the corresponding shell diameter inadult specimens. Annulations straight or very slightly obliquetoward the growth direction and regularly spaced. Very finegrowth lines, about 50 per cycle of annulations. Very finelongitudinal striae or raised lines, about five to sevenper mm. Suture line at the ridges of the annulations. Parallelsutures and annulations. Siphuncle central, slightly expandedwithin the chambers. Septal perforation about 0.07 of theshell diametre

Synonymy list

1930 Spyroceras senckenbergi n. sp. — Teichert , pp. 280, fig. 5:3,4

1984 non Spyroceras senckenbergi — Dzik , pp. 122, 125, fig. 35:5; text fig. 48a, 49.20

2006 Palaeodawsonocerina senckenbergi (Teichert, 1930) — Kröger & Isakar , pp. 154, fig. 8a, 10i,12d-e,h

2013 Palaeodawsonocerina senckenbergi (Teichert, 1930) — Kröger , pp. 34, fig. 12A, 18C

2025 Palaeodawsonocerina senckenbergi (Teichert, 1930) — Kröger , pp. 31, fig. Figs 9B, 13A, 14

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., 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

Classification

Organism group	Biota
Kingdom	Animalia
Phylum	Mollusca
Class	Cephalopoda
Subclass	Orthoceratia
Order	Orthocerida
Suborder	Orthoceratina
Family	Dawsonoceratidae
Genus	Palaeodawsonocerina
Species	nicolletoides
	senckenbergi