Permoceratoidea Miller & Collinson, 1953

Superfamily Permoceratoidea Miller & Collinson, 1953

Fig. 22 View Fig

[nom. transl., ex Permoceratidae Miller & Collinson, 1953 .]

Diagnosis

Superfamily of the suborder Domatoceratina subordo nov. with discoidal, involute conch. Suture line with distinct, deeply V-shaped external lateral and internal lobs and two small, rounded umbilical lobes.

Included family

Permoceratidae Miller & Collinson, 1953 (Early Permian; 2 genera, 2 species).

Remarks

Permonautilus , and thus the family Permoceratidae , is based on the species described by Haniel (1915) as “ Nautilus ( Aganides) bitauniensis ” ( Fig. 22 View Fig ). According to Haniel (1915) the material comes from the “Bitauni beds”, which have a late Early Permian age. Miller & Collinson (1953) discussed this species and created the new genus Permoceras and the family Permoceratidae for it. They based this taxonomic classification on the peculiarity of the suture line; in contrast to all other Permian nautilids, P. bitauniense has a complex suture with eight lobes. They compared the species with Pseudonautilus geinitzi (Oppel, 1865) from Late Jurassic strata in Moravia, a species that is almost identical in both conch geometry and suture line. Nevertheless, Miller & Collinson (1953) decided to create a new genus and family. The reason they gave was the considerable stratigraphic distance between Permonautilus and Pseudonautilus .

The family Permoceratidae was placed in the superfamily Centrocerataceae by Shimansky (1957, 1962, 1967, 1979) and in the superfamily Trigonocerataceae by Kummel (1964). Dzik (1984) did not recognise the independence of the family and placed Permoceras in the family Grypoceratidae . However, the very peculiar suture line, which differs greatly from all other Palaeozoic nautilids, justifies a separation at a high taxonomic level, and the family is therefore elevated to the rank of a superfamily.

The phylogenetic origin of Permoceras has long been considered unclear. Dzik (1984: 168, text-fig. 65) linked Permoceras as a short evolutionary lineage to Neodomatoceras , a genus with comparatively similar conch proportions but a very simple domatoceratid suture. Leonova & Shchedukhin (2023) presented Foveroceras Leonova & Shchedukhin, 2023 as a probable transitional form linking Permoceras with members of the Domatoceratidae . Foveroceras has a discoidal involute conch with a flat venter and is characterised by a deep and narrow outer lobe, a deep blunt lateral lobe, a fairly deep umbilical lobe and a very narrow deep internal lobe.