Ellesmeroceratina Flower

Dzik, Jerzy, 2020, Variability of conch morphology in a cephalopod species from the Cambrian to Ordovician transition strata of Siberia, Acta Palaeontologica Polonica 65 (1), pp. 149-165 : 162

Suborder Ellesmeroceratina Flower in Flower and Kummel, 1950

Remarks.— Teichert (1969) insisted on using the stem cerinstead to cerat- in suprafamilial rank cephalopod taxa, contrary to the old tradition and despite recommendation of the International Code of Zoological Nomenclature. He argued that both endings are allowed by the Greek grammar. In result, different stems are applied by many authors to endings of families (e.g., Ellesmeroceratidae ) and orders (e.g., Ellesmerocerida). I did not found his attitude substantiated while preparing a review of the nautiloid phylogeny ( Dzik 1984) and I continue to use the traditional endings also in this paper having support in King and Evans (2019).

Chen and Teichert (1983) elevated suborders Plectronoceratina Flower, 1964 and Ellesmeroceratina Flower in Flower and Kummel, 1950 to the ordinal rank based on the presence of expanded connecting rings and breviconic conchs in the former. As commented above, this may have been caused by the fibrous structure of the connecting rings lacking the additional firm calcified-perforate layer characteristic for Cochlioceras and more advanced nautiloids ( Mutvei 2002). In this respect the plectronoceratids do not seem to be different from the ellesmeroceratids, as exemplified by the Angara material, even if their siphuncle remained tubular.