Diagnoza

Relatively shallow flank lobe of the suture.

Porównanie

Tornoceras applanatus (Gürich, 1896) based on a specimen from the Upper Łagów beds (Sacculus-Bank) probably refers to the same species. All available specimens are minute in size, up to 22 mm in diameter, three of them with a condensation of sutures suggestive of maturity. Perhaps also Gomi-re-monomeroceras (Tornoceras) simplicius subacutum Sobolew, 1914 from the clymeniid limestone at Łagów-Dule belongs to this species, although only the shape of aperture makes it different from associated Protornoceras simplicius. In the Czarnocki’s collection housed at the State Geological Institute there is a probably adult specimen IG 284 II.290 about 52 mm in diameter, collected from the grey “Laevigites” limestone (Nodosoclymenia bed?) at Ostrówka. Its suture is characteristically simple but growth lines are not recognizable.

Another question is whether the North American type population of T. crebriseptum is truly conspecific with the Holy Cross Mountains material. Specimens from the Three Forks Shale are pyritic internal moulds with open umbilicus, which may express an increased thickness of the shell forming a kind of umbonal callus. This character was used  to substantiate transfer of the species to Pernoceras Schindewolf, 1922, the type species of which is Protornoceras kochi (Wedekind, 1908. The Montana specimens show a conical depression around umbo, resembling the Polish species of Protornoceras from Kowala in this respect but difficult to compare with specimens from Łagów and Jabłonna having the original shell preserved. The species may truly be related to P. kochi.

Autekologia

Występowanie geograficzne

Łagów-Dule and Jabłonna, Ostrówka; reworked at Sieklucki’s brickpit in Kielce.

Zasięg czasowy

C. marginifera and possibly the P. trachytera Zones, perhaps L. styriacus Zone. 

Materiały muzealne

ZPAL: 33 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.