Planetoceras Hyatt, 1893

Korn, Dieter, Miao, Luyi & Bockwinkel, Jürgen, 2022, The nautiloids from the Early Carboniferous Dalle à Merocanites of Timimoun, western Algeria, European Journal of Taxonomy 789, pp. 104-129 : 123-124

Genus Planetoceras Hyatt, 1893

Type species

Planetoceras retardatum Hyatt, 1893 ; original designation.

Diagnosis

Genus of the family Trigonoceratidae with subevolute conch; whorls slightly impressed; whorl profile rectangular with weakly flattened venter, convex flanks and narrowly rounded umbilical margin. Ornament with fine growth lines, in the preadult stage with fine spiral ridges. Suture line with shallow external and lateral lobes. Siphuncle small with subcentral position (after Kummel 1964; emended).

Included species

Planetoceras bellilineatum Miller, Dunbar & Condra, 1933 , Kentucky; Planetoceras destrictum sp. nov., Algeria; Nautilus globatus Sowerby, 1824 , Ireland; Planetoceras invenustum Shimansky, 1967 , South Urals; Planetoceras janischewskyi Shimansky, 1967 , South Urals; Planetoceras retardatum Hyatt, 1893 , Belgium; Nautilus schartimiensis Janischewsky, 1900 , South Urals; Planetoceras tiltoni Miller, Dunbar & Condra, 1933 , Iowa; Planetoceras transforme sp. nov., Algeria.

Remarks

Planetoceras was an insufficiently described and delimited genus; the type species P. retardatum was described by Hyatt (1893: 421) but not illustrated. Kummel (1964: K426) then published a photographic illustration of the type species. Miller et al. (1933: 138), Shimansky (1967: 130) and Histon (1999: 63) provided a more accurate diagnosis of the genus.

Stratigraphic range

Late Tournaisian to Bashkirian.