Polygnathus volhynicus Drygant, 1986 from K. triangularis Zone at Karczówka in the Holy Cross Mountains.

Diagnoza

P₁ elements with asymmetric platform, in juveniles lanceolate and narrow; its raised margins ornamented by transverse ribs; no apparent asymmetry in pairs; carina separate to its tip even in mature elements.

Porównanie

Juveniles show a deeper separation of the blade from marginal parts of the platform than in P. procerus, its probable ancestor. From P. praecursor, associated in some samples, the species differs in the lack of asymmetry of elements and their narrow appearance at juvenile (but not earliest) stages. Specimens of P. squalidus Drygant, 1986, co-occurring with those of P. volhynicus in the borehole Volodymyr Volynski are closely similar to mature specimens from Karczówka, and these names may be synonyms.

Autekologia

Występowanie geograficzne

Karczówka. The species occurs also in the Dębnik area. 

Zasięg czasowy

The late K. triangularis Zone. 

Materiały muzealne

ZPAL: 1,893 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.