The type specimens of Cyrtoceras ellipticum Lossen 1860 and proposedly conspecific material from Baltic erratic boulders of late Llanvirn (Lasnamägian) age are closely similar to Phthanoncoceras oelandense Evans & King 1990 from the latest Arenig (early Kundan) of Sweden. Cyrtoceras priscum Eichwald 1861, co-occurring with C. ellipticum, is generically distinct in its short living chamber and much more advanced siphuncular structure; it probably represents Oonoceras lineage. The type of Orthoceras damesi Krause 1877 from the Baltic Beyrichienkalk erratic boulders, which is smooth, except for faint growth lines, appears to represent a later ontogenetic stage in development of a kionoceratid with prominent longitudinal riblets and annulations at early stages. It is probably a derivative of the main longiconic lineage of Spyroceras, in which prominent conch ornamentation disappeared in adult specimens.