Polonoceras sudeticum (Renz, 1914) from the P. jugosus (or D. trigonica) Zone at Dzikowiec in the Sudetes.

Diagnoza

Closed umbilicus of conical appearance demarkated by a spiral ridge; roundly tabulate venter; serial constrictions on conch flanks parallel to the aperture, which bears acute auricles; suture with a deep, narrow flank lobe.

Porównanie

Renz (1914) identified his only specimen from Dzikowiec lacking any suture as a new variety of Oxyclymenia ornata. The constrictions (not internal thickenings!) in its conch, expressed both on nuclei and the conch surface, are so characteristic that there is little doubt that the newly collected topotype specimens are conspecific. The acute auricles and deep lobe of the suture point to Polonoceras dorsoplanum as the ancestor of the species.

Autekologia

Występowanie geograficzne

Dzikowiec.

Zasięg czasowy

P. jugosus (or D. trigonica) Zone.  

Materiały muzealne

ZPAL: 3 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.