Gatunek typowy
Pseudopolygnathus prima Branson et Mehl, 1934 from the Tournaisian of Missouri.

Opis

Diagnosis. — Icrion in P1 elements composed of rows of tubercles and frequently a longitudinal ridge, basal cavity wide and shallow.

Remarks. — The Devonian species attributed here were classified in Bispathodus Müller, 1962, although its type species Spathodus spinulicostatus E. R. Branson, 1934 is of Early Carboniferous age. Its holotype, similar to that of S. costatus, is probably the end member of the variability range of the co-occuring type species of Pseudopolygnathus, P. primus, as suggested by samples from elsewhere. Whatever is the real nature of this specimen, these genera are clearly closely related and there is no way to distinguish them in a satisfactory way.
The icrion developed independently in the branch of P. jugosus and P. ziegleri from the ancestral situation of P. stabilis. However, P. ostrovkensis, with its robust and wide icrion, appears earlier at Kowala than P. jugosus, much less advanced in this respect. Perhaps Pseudopolygnathus, as understood here, is truly polyphyletic and the P. jugosus lineage should be classified in Dasbergina.

Synonimy

Zasięg czasowy

Literatura

Dzik, J. 2006. The Famennian "Golden Age" of conodonts and ammonoids in the Polish part of the Variscan sea. Palaeontologia Polonica 63, 1-359.