Scyphoceratoidea Ruzhencev & Shimansky, 1954

Superfamily Scyphoceratoidea Ruzhencev & Shimansky, 1954

Fig. 40 View Fig

Diagnosis

Superfamily of the suborder Solenochilina , in which the conch is cyrtoconic and rapidly increasing in width and height, with a round or somewhat angular whorl profile. Body chamber large, phragmocone chambers small. Sculpture of transverse ribs or missing. Siphuncle adjacent to the ventral side or close to it. Suture line straight or with small lobes (after Shimansky 1967).

Included families

Scyphoceratidae Ruzhencev & Shimansky, 1954 (Early Carboniferous to Early Permian; 6 genera, 14 species).

Dentoceratidae Ruzhencev & Shimansky, 1954 (Late Carboniferous to Early Permian; 1 genus, 5 species).

Neptunoceratidae Shimansky, 1957 (Late Carboniferous; 2 genera, 4 species).

Remarks

The superfamily Scyphoceratoidea is so far only very poorly known because its representatives are generally very rare and have only been discovered in a few localities. In addition, the individual occurrences are of isolated stratigraphic age and are therefore difficult to integrate into a phylogenetic scenario. It is not even clear whether the genera grouped together in the superfamily actually form a monophyletic unit.

In the “ Osnovy ”, Shimansky (1962: 117) placed the family Neptunoceratidae in the superfamily Rutocerataceae , while he included the families Scyphoceratidae and Dentoceratidae in the superfamily Aipocerataceae , both belonging to the suborder Rutoceratina . Later ( Shimansky 1967, 1979) he combined the three families into the superfamily Rutocerataceae .

Meanwhile, Flower (1963) discussed these problems in detail and outlined the various possible origins of the scyphoceratids and related cephalopods. However, he did not present a clear phylogenetic scenario.

Kummel (1964: K442) merged the Dentoceratidae with the Scyphoceratidae and placed them in the superfamily Aipocerataceae . Teichert (1964a: K484) included the family Neptunoceratidae among the “doubtful taxa”. This was mainly due to the discussion by Furnish et al. (1962), who suggested that the specimens of Tetrapleuroceras and Neptunoceras were merely growth stages of Brachycycloceras Miller, Dunbar & Condra, 1933 and therefore belonged to their family Brachycycloceratidae ( Furnish et al. 1962) . This hypothesis was also taken up by Dzik (1984: 130), who considered not only the Neptunoceratidae but also the Scyphoceratidae to be synonymous with the Cycloceratidae Hyatt in Zittel, 1900. He only accepted the two genera Neptunoceras and Scyphoceras as valid.

Niko & Mapes (2011) discussed the systematic position of the Neptunoceratidae ; they concluded that the family does not fit into either the order Nautilida or the family Cycloceratidae due to its combination of characters. They therefore rejected the classification schemes advocated by Shimansky (1967) and Dzik (1984) and left the systematic classification in uncertainty. King & Evans (2019: 71) discussed the similarity of Brachycycloceras and Texanoceras Niko & Mapes, 2011 and suggested that both genera may be better assigned to the Nautilida .

Due to the lack of new material, the problems identified cannot be resolved at present. Therefore, the families ( Fig. 40 View Fig ) in question are tentatively placed in the Aipoceratoidea without further discussion.