Polonoceras bashkiricum Bogoslovsky, 1971 from the C. marginifera Zone from Jabłonna  and  Łagów in the Holy Cross Mountains.

Diagnoza

Acute tips of auricles of the aperture; distinctly tabulate venter of mature specimens, rounded in juveniles.

Porównanie

The Frasnian-style suture and the subtrapezoidal cross section of the whorl make this specimen similar to the holotype of //Linguatornoceras linguum//. Conchs of the Famennian species are attributed to the genus , however, different from the Łagów specimen in having a very narrow flank lobe of the suture and rounded margins of the umbilicus. In the latter aspect, the specimen discussed resembles the stratigraphically older species attributed here to //Gundolficeras// //korni// (Becker, 1993) and //Protornoceras simplicius//, being different in the subtrapezoidal whorl section and deep flank lobe of the suture. Specimens from sample Ł-14 tentatively attributed to the latter species may also belong here, as well as the specimen from the Upper Łagów Beds illustrated by Sobolew (1914) as //Tornoceras escoti// Frech, 1902. The species seems both morphologically and stratigraphically transitional between //P. sandbergeri// and //P. planum//.

Autekologia

Występowanie geograficzne

Jabłonna; Łagów-Dule; possibly also reworked at Sieklucki’s brickpit in Kielce.

Zasięg czasowy

Late K. crepida (bed 15) and probably the C. marginifera (bed 17) Zones; the C. marginifera 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.