Polygnathus znepolensis Spassov, 1965 from the P. jugosus Zone at Ostrówka in the Holy Cross Mountains and Gołogłowy in the Sudetes.

Polygnathus znepolensis - P₁ element

Diagnoza

Anterior part of the platform in P₁ element ornamented with oblique ribs, posterior lobe wide and gently convex, smooth.

Porównanie

This is a species widely occurring in shallow-water Late Famennian environments. In the holotype of P. znepolensis re-illustrated by Klapper  the posterior lobe of the platform bears robust radiating ridges, which have not been encoutered in any of the mature specimens in the Polish material. Possibly the holotype belongs thus to P. extralobatus, its close relative and probable ancestor. Both species co-occur at Gołogłowy and Ostrówka. In the oldest samples containing the species only minute juvenile specimens occur. This may reflect either a high juvenile mortality in extreme environments atypical for the species or its paedomorphic origin.

Autekologia

Występowanie geograficzne

Jabłonna, Ostrówka, Kowala, Gołogłowy, and Dzikowiec. The species occurs also in the Dębnik area.

Zasięg czasowy

Late L. styriacus and P. jugosus Zones.  

Materiały muzealne

ZPAL: 445 specimens.

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.