Richardsonoceras Foerste, 1933

Kröger, Björn, 2025, The Lyckholm acme of cephalopods - Review of the late Katian (Vormsi-Pirgu regional stages) Ordovician cephalopods of Estonia, European Journal of Taxonomy 978, pp. 1-169 : 89

Genus Richardsonoceras Foerste, 1933

Type species

Cyrtoceras simplex Billings, 1857 , from Nepean township, Ottawa, Ontario, Canada, Leray Formation, Sandbian; by original designation.

Diagnosis

Gradually enlarging strongly curved shells; cross section compressed with elliptical to oval cross section, convex side of conch curvature more narrowly rounded; adult body chamber slightly contracted adorally; sutures with shallow lateral lobe, slightly oblique sloping slightly adapically on the antisiphuncular side; siphuncle small, close to margin on convex side of conch curvature; segments slightly expanded. (Adopted from Kröger et al. 2009b: 286.)